Recent its_path_reports items

Tools for Demand-Supply Assessment of EV Charging Infrastructure and Strategy Evaluation of Smart Charging

Tue, 2 Jun 2026 00:00:00 +0000

California’s transition to electric vehicles (EVs) requires more than additional charger counts. Public charging must be accessible, affordable, and reliable where people actually live and travel. This report presents a geospatial dashboard and time-series toolkit for the nine Bay Area counties that maps public charging stations, tracks price and charging-port status at 10-minute intervals, and identifies disadvantaged community (DAC) census tracts using the joint U.S. Department of Energy/U.S. Department of Transportation/National Electric Vehicle Infrastructure (DOE/DOT/NEVI) framework. The tool reports charger availability, utilization, pricing, reliability, and average session cost, and supports equity metrics such as ports per 1,000 residents or renters, travel time to a direct-current fast charger, and tract-levelcomparisons between DAC and non-DAC areas. It also supports early screening of sites for Level-3 fast chargers by identifying locations that appear feasible from...

Drivers’ Responses to Eco-driving Applications: Effects on Fuel Consumption and Driving Safety

Thu, 4 Sep 2025 00:00:00 +0000

Onboard eco-driving systems provide drivers with real-time information about their driving behavior and road conditions, encouraging them to optimize their driving speed and consequently reduce fuel consumption and emissions. However, there are barriers to making eco-driving a habit. To determine the elements that influence drivers’ intentions to practice eco-driving and their acceptance of eco-driving technology, we developed a theoretical model based on established theories on planned behavior, technology acceptance, and personal goals. The findings showed that drivers’ intention to practice eco-driving has an indirect effect on their intention to use the system via the factor of perceived ease of use. We also explored how cognitive distraction while using an eco-driving system can be a potential barrier to acceptance. The intent is to put forward a solution to improve drivers’ usage eco-driving by turning off guidance when the system detects that the driver is experience from...

Traffic Operations Data Standards: Task ID 4085 (65A1019)

Mon, 4 Aug 2025 00:00:00 +0000

Transportation data standards are an increasingly important and complex topic, as well as a key enabler of Intelligent Transportation Systems (ITS). New data sources, private data providers, and uses for transportation data are exploding. The ability to harness data is at the core of modern efforts to improve the safety of our transportation system and advance mobility for the benefit of all. There is an increasing need for automated data exchange between public agencies and private organizations to improve existing operations and enable new products and services. In addition, the provision of public safety is another overlapping area where first responders require up-to-date and reliable information to succeed in theirmissions.

Improving the Traffic Census and Highway Performance Monitoring System (HPMS) Programs

Wed, 4 Dec 2024 00:00:00 +0000

The objective of this research study was to support the Traffic Census and Highway Performance Monitoring System (HPMS) Programs in identifying locations for motorized traffic data collection on public roads in California. The study analyzed the traffic census count locations for each District to determine at which Census count locations the automated and continuously collected Caltrans Performance Measurement System (PeMS) data could be used in lieu of manual traffic counts. Next, this research identified and evaluated count locations for motorized traffic data collection on non-State Highway System Routes to help meet Federal Highway Administration (FHWA) requirements for the Caltrans Highway Performance Monitoring System (HPMS) program. Lastly, this research reviewed and summarized the emerging traffic data collection technologies and data sources appropriate for Caltrans HPMS and/or Census reporting purposes.

Field Experiments Demonstrate Fuel Savings for Close-Following

Mon, 4 Nov 2024 00:00:00 +0000

There are only two ways to increase the throughput of vehicles on a highway—either construct more freeway lanes, or accommodate a shortened average spacing between individual vehicles (while maintaining speed). Providing a rational means for close-following is an attempt to accomplish the latter. The maximum throughput for a typical freeway lane is about 2000 vehicles/hour, and is roughly independent of the attributes of any particular freeway. The number is remarkably inelastic varying little over the past twenty years in spite of great improvements in the design of freeways and in the handling characteristics of automobiles (see Browand, Zabat & Tokumaru, 1997, for a recent example). Surprisingly, the average vehicle spacing at maximum throughput is approximately 35 meters. Shortening this headway to the order of a car length (five meters, typically) while maintaining a high speed would provide a significant improvement in throughput....

Early Opportunities to Apply Automation in California Managed Lanes

Wed, 23 Oct 2024 00:00:00 +0000

Connected and automated vehicles hold the potential for substantial improvements to traffic safety, travel time reliability, roadway capacity, and environmental impacts and managed lanes have the potential to be ideal testbeds for CAV technologies. The purpose of this report is to identify specific opportunities to leverage California’s managed lane network as early experimental and pilot deployment sites for CAVs. To this end, we have conducted a detailed inventory of the managed lane facilities in California and applied evaluation criteria to identify two promising sites for future CAV tests and initial deployments. Our study recommends the I-15 Express Lanes in San Diego and the I-10 Express Lanes in Los Angeles for future CAV tests.

Reimagining Sensor Deployment

Thu, 5 Sep 2024 00:00:00 +0000

The California Department of Transportation (Caltrans) collects megabytes of data every day using a dedicated traffic sensing infrastructure. The collected data provide support for traffic management and system performance monitoring activities that are crucial for supporting the agency’s mission, vision, and strategic goals to strengthen stewardship and drive efficiency. Operating this vast detection system requires extensive resources in the form of engineering and maintenance support, along with millions in capital funds to keep the system running. Within the above context, alternate hybrid data collection models utilizing purchased or third-party data to augment existing data collection system capabilities may enable a reduction in the number of physical detection stations required while maintaining suitable accuracy for Caltrans’ purposes. In addition to the potential for cost savings, the reliance on fewer physical sensors also offers the potential to reduce the exposure...

Hybrid Traffic Data Collection Roadmap: Pilot Procurement of Third-Party Traffic Data

Wed, 31 Jul 2024 00:00:00 +0000

This research investigates the feasibility and the business case for purchasing third‐party probe data and fusing it with Caltrans’ existing data for the purpose of estimating travel times. The intent was to demonstrate an efficient and cost-effective use of alternative traffic data sources to complement the detection systems currently installed and operated by Caltrans.

Hybrid Traffic Data Collection Roadmap: Objectives and Methods

Wed, 31 Jul 2024 00:00:00 +0000

Traffic data is used to estimate current traffic conditions so that travelers and agencies can make better decisions about how to use and manage the transportation network. This research explores the fusion of probe data (vehicle speed and direction) with loop data (density, speed, and count) in the context of producing overall network speed and travel time estimates. Speed and travel time estimates are useful in many circumstances, but current system control strategies (ramp metering, for example) require density data. While it is difficult to significantly increase the quantity of loop detectors on state highways, the penetration rate of probe data is continually increasing. Multiple data sources with various characteristics were fused by running probe and loop data through the Mobile Millennium highway model, generating velocity maps and travel times. The performance of data sources both individually and when fused was evaluated. It was found that the highest quality estimates...

Reduce Emissions and Improve Traffic Flow Through Collaborative Autonomy

Fri, 10 May 2024 00:00:00 +0000

This report explores opportunities for employing autonomous driving technology to dampen stop-and-go waves on freeways. If successful, it could reduce fuel consumption and emissions. This technology was tested in an on-road experiment with 100 vehicles over one week. Public stakeholders were engaged to assess the planning effort and feasibility of taking the technology to the next level: a pilot involving 1000+ vehicles over several months. Considerations included the possible geographical boundaries, target fleets of vehicles, and suitable facilities such as bridges or managed lanes. Flow smoothing technology may improve the user experience and operations of managed lanes or bridges, however it may require external incentives such as reduced tolls to entice the traveling public to use it. This must be matched with other goals such as verifying vehicle occupancy. It might be possible for some hybrid solution that addresses both challenges to provide a way forward. A concept of...

A Futures Market for Demand Responsive Travel Pricing

Fri, 10 May 2024 00:00:00 +0000

Dynamic toll pricing based on demand can increase transportation revenue while also incentivizing travelers to avoid peak traffic periods. However, given the unpredictable nature of traffic, travelers lack the information necessary to accurately predict congestion, so dynamic pricing has minimal effect on demand. Dynamic toll pricing also poses equity concerns for those who lack other travel options. This research explores a potential remedy to these concerns by using a simple “futures market” pricing mechanism in which travelers can lock in a toll price for expected trips by prepaying for future tolls, with the future price increasing as more travelers book an overlapping time slot. This approach encourages travelers to avoid driving during the peak periods when pricing increases toward capacity or to purchase trips in advance when the price remains low or discounted, thus using infrastructure capacity more efficiently. Travelers that do not prepurchase their trip are subject...

Deliver a Set of Tools for Resolving Bad Inductive Loops and Correcting Bad Data

Fri, 22 Mar 2024 00:00:00 +0000

This report documents a practical work conducted at California PATH for developing a portable tool to be used at the control cabinet level to accurately diagnose any fault(s) of a loop detection system (including loop circuits, loop cards, cable links, etc.), to check the detection accuracy, to deal with sensitivity of detector card, and to correct the faulty data. To achieve these functionalities at the low level, it is necessary to utilize an independent source as a baseline data to compare against the loop detection system output. Such a comparison also permits an evaluation of the loop system. Since multiple-vehicle tracking technologies using digital video camera on freeways have been well-developed and tested at PATH, it is used as the baseline measurement in the portable tool for the loop fault diagnosis. This report presents the development of a prototype system including the hardware, the software, the data communication method, and the algorithms. Some preliminary consideration...

Travel Behavior of Immigrant Groups in California

Fri, 22 Mar 2024 00:00:00 +0000

California is the destination for over one-quarter of immigrants to the United States, and immigrants now make up over one-quarter of the state’s population, with nearly half of immigrants originating in Mexico. To ensure that transportation systems and services adequately meet the needs of recent immigrants, planners need a firm understanding of the travel behavior of immigrant groups. This paper reports on key findings from a three-phased study: (1) analysis of data on commute travel of California immigrants from the 1980, 1990, and 2000 Censuses; (2) focus groups with recent Mexican immigrants in six California regions on their transportation experiences and needs in six California regions; and (3) interviews with community-based organizations in nine California regions on the transportation needs and wants of Mexican immigrants. Analysis shows that the car is the most important means of transportation for immigrants; nearly two-thirds of all immigrants use single occupancy...

Red-Light-Running Collision Avoidance

Fri, 22 Mar 2024 00:00:00 +0000

Red light running (RLR) problem has been recognized as a significant safety problem in California as well as throughout the United States. This paper follows a two step process to develop enhanced signal timing models for possible reduction of RLR. In the first step, field data are collected with one-second resolution and discrete choice models are estimated to determine the significant influencing factors of RLR; in the second step, based on the findings from the first step, T7F software package as well as custom designed programs is used to find the enhanced signal timing plans that can potentially reduce RLR, while at the same time maintain the commonly used signal control objectives, such as intersection delay. Future research direction is also discussed.

Interim Report: Compliance and Commercial Vehicle Operators – A Systems Evaluation of the Problem and Virtual Solutions

Fri, 22 Mar 2024 00:00:00 +0000

This report documents a review of the literature for commercial motor vehicle inspection and compliance stations and its relationship with the growth of truck travel over the next 25 years and the lack of concurrent capacity increases in staffing at such stations. Problems result in that more commercial vehicles will need to stop for inspection with longer queues at weigh stations associated with increased congestion, increased wait times, more idling trucks, and increased safety hazards. Alternatively, without stopping at inspection and compliance stations other problems will result such as roadway pavement and structure damage, and safety-related and security-related issues. Proposed advanced technological solutions to these problems are examined focusing on the four areas of pavement damage, safety, air quality, and security.

The Freeway Performance Measurement System (PeMS), PeMS 9.0: Final Report

Fri, 22 Mar 2024 00:00:00 +0000

Under development and operation since 1999, PeMS now is the de facto repository for all Caltrans fixed-location detector data. The PeMS 9.0 effort completed seven tasks: (1) Control Algorithm Support; (2) Integration of Census Data in PeMS; (3) Investigation of Fidelity of 3rd Party Detectors; (4) OD estimation algorithm based on the fusion of the FasTrak data and the ITS-sensors; (5) Incorporating speed measurements reported from the field; (6) Incorporation of New Photolog Format; and (7) Development of Diagnostic Routines for Rural Facilities.

Evaluation of an Animal Warning System Effectiveness

Fri, 22 Mar 2024 00:00:00 +0000

The problem of vehicle/animal crashes is being addressed in this research. There have been a few new technologies that claim to accurately detect the large animals that cross our roadways. Each one has its own strengths and shortcomings. A close attention must be given to the selected site and the technology deployed based on its weather, vegetation, topography, and local animal types and sizes. In this project, we have reviewed a number of animal detection systems and selected one system with the most potential to serve the characteristics of the selected site and the local Deer. We did a preliminary test of the reliability of this system in a testbed in Lewistown, Montana. The results were encouraging. We also carefully selected a site that we felt could benefit the most from this safety improvement based on its physical and climatic characteristics as well as its high number of vehicle/animal crashes. We also designed and developed a data monitoring and recording system that...

Evaluate the Causes of Pedestrian and Bicyclist Traffic Fatalities and Injuries, and Establish Appropriate Countermeasures for Use in California

Fri, 22 Mar 2024 00:00:00 +0000

The three primary objectives of this project were to: (1) conduct research on existing bicycle and pedestrian safety programs and guidelines in the U.S. and internationally, (2) obtain and analyze existing data related to pedestrian and bicycle safety in California, and (3) assist in developing methodologies for producing safety action plans, identifying and selecting projects, conducting education campaigns, and targeting enforcement campaigns. To meet these objectives, SafeTREC developed a set of resources and tools for use in California. These resources make information and data on pedestrian injuries and fatalities in CA accessible to practitioners, researchers, and anyone else interested in obtaining information and improving conditions for pedestrians. The deliverables are individually summarized and included as appendices. These resources should be further developed and maintained to remain useful and appropriate.

Cooperative Adaptive Cruise Control: Testing Drivers’ Choices of Following Distances

Fri, 22 Mar 2024 00:00:00 +0000

A Cooperative Adaptive Cruise Control (CACC) system has been developed by adding a wireless vehicle-vehicle communication system and new control logic to an existing commercially available adaptive cruise control (ACC) system. The CACC is intended to enhance the vehicle-following capabilities of ACC so that drivers will be comfortable using it at shorter vehicle-following gaps than ACC. This can offer a significant opportunity to increase traffic flow density and efficiency without compromising safety or expanding roadway infrastructure.

This report describes the design and implementation of the CACC system on two Infiniti FX-45 test vehicles, as well as the data acquisition system that has been installed to measure how drivers use the system, so that the impacts of such a system on highway traffic flow capacity and stability can be estimated. The results of quantitative performance testing of the CACC on a test track are presented, followed by the experimental protocol...

Development of Performance-Based Specifications for Efficient Deployment of Advanced Public Transportation Systems (EDAPTS)

Fri, 22 Mar 2024 00:00:00 +0000

Efficient Deployment of Advanced Public Transportation Systems (EDAPTS) Smart Transit System was developed by California Polytechnic State University, San Luis Obispo in a previous research effort from 1997 to 2007. California Partners for Advanced Transit and Highways (PATH) and the California Department of Transportation (Caltrans) have sponsored follow-on research to develop performance-based specifications for the EDAPTS system. These specifications are intended to facilitate industry adoption and widespread deployment of EDAPTS transit management system. The EDAPTS Performance Specification was developed by reviewing industry performance specification best practices, identifying all unique EDAPTS elements, determining appropriate performance metrics for each element, and determining these performance metrics. All EDAPTS elements and their associated performance metrics were organized and imported into a database for ease of analysis and automated performance specification...

Field Demonstration and Tests of Lane Assist/Guidance and Precision Docking Technology

Fri, 22 Mar 2024 00:00:00 +0000

This document reports the improvement and implementation of the magnetic lane-guidance and precision docking system on a 60ft articulated bus and the extensive testing on a 0.9 mile test track installed with magnets along southbound East 14th Street, San Leandro, California between 139th and 150th Avenue on a real-world operation setting. The extensive testing in the real-world setting provided valuable opportunities to discover and thus resolved a number of issues that might have prevented the system from achieving high repeatability and reliability in the future deployment on a large, public scale.

Video Vehicle Detector Verification System (V2DVS)

Fri, 22 Mar 2024 00:00:00 +0000

A practical need to assess the accuracy and attributes of each of the many types of roadway sensors and detectors motivated the California Department of Transportation to construct a traffic detector test bed on I-405 in Southern California. With up to ten detectors of different types under concurrent test in each of six lanes, a means for automating the testing process became imperative, since traditional human verification methods were not practical.

This project involved the development of an automated data acquisition and verification system that utilizes a consensus of the results from all detectors under test, along with those of a reference image processing system, to create a preliminary ground truth record requiring manual verification for only a small percentage of ambiguous cases. Individual detector performance is then assessed by comparison with this verified dataset. The test bed architecture, data fusion methodology, and computer vision methods are unique...

Addressing Equity Challenges to Implementing Road Pricing

Fri, 22 Mar 2024 00:00:00 +0000

Many public officials looking for ways to increase the efficiency, equity, and financial stability of transportation systems are turning to metering road use with electronic tolls. While tolling today is easier and cheaper than ever, officials face many obstacles to implementing tolling – especially concerning equity. Accordingly, this paper examines road pricing equity from a variety of perspectives. We begin by developing an evaluation framework that defines three distinct bases for evaluating equity – free markets, equal opportunities, and equal outcomes. We then use this framework to guide a review of five case studies of road pricing – in San Diego, Minneapolis-St. Paul, Germany, Stockholm, and New York – that explore how equity concerns have been raised and addressed in practice. We find that equity was a central question in each case, alternatively motivating (1) the implementation of pricing (Germany), (2) the funding of alternative modes...

SafeTrip 21 Initiative: Networked Traveler Foresighted Driving Field Experiment Final Report

Fri, 22 Mar 2024 00:00:00 +0000

This report describes the SafeTrip-21, Networked Traveler Foresighted Driving Field Experiment conducted as part of the US DOT’s SafeTrip-21 initiative. This experiment developed and evaluated an Advanced Driver Assistance System providing soft-safety or situational awareness alerts regarding “Slow Traffic Ahead” when driving on a freeway. The Networked Traveler system detects slow traffic or queues at several thousand locations in the Bay area, monitors the locations and speeds of its test subjects as they drive, and determines if the driver is approaching the slow traffic fast enough to warrant an alert. If so, the system alerts the driver through an auditory interface. The desired outcome is a foresighted reduction in speed, resulting in a smoother overall transition into the oncoming traffic queue. The system aims to reduce the likelihood of end-of-queue crashes on freeways, this being a subset of the class of rear-end crashes. The hypothesis is tested by computing measures...

Feasibility Study for the Use of Biodiesel in the Caltrans Fleet

Fri, 22 Mar 2024 00:00:00 +0000

Over the past several years, biodiesel use has dramatically increased due to its potential emissions benefits, classification as a low-carbon/renewable fuel and ability to be integrated into diesel fleet applications without significant infrastructure or other substitution issues. Caltrans has largest fleet in California, so biodiesel would provide many benefits in terms of meeting environmental and energy security objectives. However, all aspects of biodiesel use needed to be thoroughly investigated, including potential benefits and liabilities, prior to widespread introduction into the Caltrans fleet. In this research project, the University of California, Riverside (UCR) completed a thorough literature investigation, surveyed current users, attended national technical sessions designing the strategic road-map and reviewing the progress for biodiesel, wrote specifications for Caltrans purchase of biodiesel and carried out a twelve-month field demonstration at Indio. Results...

Estimating Pedestrian Accident Exposure

Fri, 22 Mar 2024 00:00:00 +0000

We are pleased to present the final report of Caltrans Task Orders 5211 and 6211, “Estimating Pedestrian Accident Exposure.” The project focused on defining pedestrian exposure and evaluating methods for measuring it within the State of California. The project was funded by the California Department of Transportation as part of the California Partners for Advanced Transit and Highways (PATH) Program of the University of California.

Deliverables associated with the project include (I) a protocol report on assessing pedestrian exposure, which is accompanied by a training curriculum and an evaluation of manual pedestrian counting methods; (II) an evaluation and test of automated pedestrian counting methods; and (III) a report on strategies to create a statewide pedestrian exposure database and (IV) a protocol for Pedestrian Exposure Study in Alameda County. The deliverables are discussed in more detail below.

Investigation of Elderly Driver Safety and Comfort: In-Vehicle Intersection “Gap Acceptance Advisor” and Identifying Older Driver Needs

Tue, 19 Mar 2024 00:00:00 +0000

Our work in Toyota GapAdvise is comprised of two interrelated elements: identify driving task challenges, and a pilot study on one particular class of decision support system, an intersection gap advisor. From these elements, we have recommended countermeasures and potential design guidelines for the elderly driving population in the United States.

We performed our work in the following sequence of technical tasks, each corresponding to a section heading in this final report:

Determine Extent of Problem (Task 1). From crash databases and demographic data, we have determined the projected extent of the problem, extending from past work. From our synthesis and interpretation of data and publications, we have ranked causal factors.

Conduct Focus Group and Observational Analysis of Elderly Drivers (Task 2). Through focus groups and observing elderly drivers in their own vehicles, we have developed an understanding of the problems faced by elderly drivers.

Conduct...

Developing Calibration Tools for Microscopic Traffic Simulation Final Report Part II: Calibration Framework and Calibration of Local/Global Driving Behavior and Departure/Route Choice Model Parameters

Tue, 19 Mar 2024 00:00:00 +0000

The central goal of this research is to develop a systematic framework and the support tools to ease, streamline and speed up the calibration of micro simulation projects. Part II of the final report documents the accomplishments achieved in the first phase of the research project(a review of practice and calibration guidelines is documented in a Part I). These accomplishments include: 1) developed a calibration framework that decouples the calibration process into five components: project scoping and error checking, global parameter calibration, local parameter calibration, departure/route (D-R) choice parameter calibration, and global calibration, 2) developed GA-based calibration tools for local and global parameters, as well as D-R choice parameters, 3) integrated the developed tools into one user-friendly graphical interface, and 4) tested the developed methods and tools on synthetic and real networks. It is shown by working examples that the developed tools can help achieve...

A Tool for the Incorporation of Non-Recurrent Congestion Costs of Freeway Accidents in Performance Management

Tue, 19 Mar 2024 00:00:00 +0000

In this research, we develop and apply an analytic procedure that estimates the amount of traffic congestion (vehicle hours of delay) that is caused by different types of accidents that occur on urban freeways in California. A key feature of this research is the development of a method to separate the non-recurrent delay from any recurrent delay that is present on the road at the time and place of a reported accident, in order to estimate the contribution of non-recurrent delay caused by the specific accident. Our analysis involves a case study of accidents that occurred on freeways in Orange County in 2001. The non-recurrent delay caused by the case study accidents is estimated based on inferred link speeds derived from loop data and a binary integer programming formulation to identify the temporal and spatial region affected by the accident. Computations of non-recurrent delay were successfully performed for 870 accidents that occurred on weekdays throughout the period of March...

On-Ramp Metering Experiments to Increase Freeway Merge Capacity

Tue, 19 Mar 2024 00:00:00 +0000

Observations of two freeway/on-ramp merges unveil the mechanism that causes their capacities to diminish when queues form just upstream. Field experiments at one of the sites demonstrate that by responding to occupancies measured near the merge, ramp metering can reverse this mechanism, or postpone its occurrence, and thereby generate higher merge capacities. Detailed observations at the second site imply that higher merge capacities can also be achieved using traffic control schemes that regulate inflows to the merge from the freeway shoulder lane. Collectively, the findings point to further experiments needed to refine capacity-enhancing control schemes so that such schemes might enjoy wide spread deployment.

California Trains Connected

Tue, 19 Mar 2024 00:00:00 +0000

This project is to assist the Capitol Corridor Joint Power Authority (CCIPA) and the California Department of Transportation (Caltrans) assemble a decision framework for selecting wireless Internet access on behalf of customers riding the three California State sponsored Intercity Rail Services. To accomplish this objective, we researched the state of worldwide deployment of service based on the wireless technologies, such as wireless fidelity (WiFi) and Worldwide Interoperability for Microwave Access(WiMAX), conducted a survey of the WiFi service at San Francisco Airport, and examined the historical ridership data on train routes of the Intercity Rail service. In addition, we conducted a survey on the trains offering trial Internet access based on low bandwidth communication infrastructure. The results are used with other data to develop business model options.

To support the business mode options, the project technical team researched the wireless technology landscape,...

Lane Assist Systems for Bus Rapid Transit, Volume I: Technology Assessment

Tue, 19 Mar 2024 00:00:00 +0000

This report documents the information collected by an FTA-led delegation to several European organizations that have had experience in the development and operation of transit lane assist systems based on three different technologies, including (1) optical guidance in Rouen, France, (2) magnetic guidance in Eindhoven, Netherlands and (3) mechanical guidance in Essen, Germany. It includes summaries of the briefings prepared by the European hosts in response to questions from the delegation, the discussions the delegation had with their hosts and observations based on riding the systems in public service. This report is accompanied by a CD ROM that includes the presentations given by the various hosts during the visit and pictures taken by the members of the delegation.

An Optimal Resource Allocation Tool for Urban Development Using GIS-based Accessibility Measures and Stochastic Frontier Analysis

Tue, 19 Mar 2024 00:00:00 +0000

Assessments of transportation investment from a “social efficiency” viewpoint are absent from transportation policy analysis and marketing practice. This is mainly due to the lack of tools capable to assess the role of transportation infrastructure investment on the provision of activity opportunities to residents of each locality. In this report, we demonstrate a tool that identifies specific locations in an entire state where resource allocation has succeeded in maximizing benefits to the public. In addition, the tool and the Geographic Information System maps derived from this tool show which locations in California fail to be optimal and require their residents to travel excessively to pursue the same amount of activities when compared to other optimal locations around the state where travelling enables better time allocation. Efficiency is measured using stochastic frontier regression analysis and a wide variety of derived land use and transportation infrastructure indicators...

California Intersection Decision Support: A Systems Approach to Achieve Nationally Interoperable Solutions II

Tue, 19 Mar 2024 00:00:00 +0000

The overall IDS research plan was constructed to realize, in slightly more than three years, the requirements, tradeoffs assessment, and technology investigations necessary to define an IDS. Toward the end of the project we will combine our understanding of the problem definition, IDS technologies and our integration experience with a standard Caltrans intersection (with advanced controller) and design a deployable IDS demonstration that can be field-tested.

With the availability of sensing, communication, and computing technologies, IDS systems are promising for the reduction of crashes, fatalities, and injuries on the roadway. Currently, Federal and State governments are partnering with private industries and academia institutions to pursue the deployment of intersection decision support (IDS) and cooperative intersection collision avoidance systems (CICAS), which seek to combine infrastructure-based and vehicle-based functions to provide optimal solutions for roadway...

Development of Bus Rapid Transit Information Clearinghouse

Tue, 19 Mar 2024 00:00:00 +0000

This report documents the development of the bus rapid transit information clearinghouse, which is a web-based informational tool on bus rapid transit systems. It may be accessed at the following website address: http://path.berkeley.edu/informationclearinghouse/. This web-based tool provides users with a comprehensive and organized first-stop way of performing bus rapid transit-related research and investigations. The initial version of the BRT Information Clearinghouse has three primary elements consisting of the Planning Support Tool, the Publications Database, and BRT Resources. The Planning Support Tool provides users directly with or pointers to information resources by walking users through the scope of a given situation and the nature of the issues being addressed to arrive at a set of resources to provide the necessary support. The Publications Database provides access to fully abstracted records of published and/or otherwise publicly available materials from professional...

Advanced Bus Stops for Bus Rapid Transit

Tue, 19 Mar 2024 00:00:00 +0000

The Santa Clara Valley Transportation Authority (VTA) is planning a bus rapid transit route on the alignment of its busiest existing route, with 30 stops in each direction. This study was conducted to determine how new technology could best be used to improve these bus stops as well as bus stops on other VTA routes and other bus systems. The study focused on bus passengers’ needs and preferences, available technologies, and the combination of improvements that would be most valued by passengers.

Passenger activities at the main bus stop were observed, an on-board passenger survey was conducted on the existing route, and a focus group of VTA passengers was convened to gain feedback on potential bus stop improvements. Schedule information, clean surroundings, shelters, benches and lights were found to be what the greatest number of people wanted at bus stops. Also highly valued was the time at which the next bus would arrive. Seventy-three percent of passengers surveyed...

Global Warning Signal Integration as a Tool for Work Zone Safety and Efficiency

Tue, 19 Mar 2024 00:00:00 +0000

A work zone (WZ) is visually confusing, and while no WZ looks like any other, they all share a common feature. All of them present an array of flashing light signals which are especially prominent at night. These signals ignite with no relation to one another. Each, by itself, is designed to be highly visible, attention-getting and salient, being positioned high on vehicles, along barriers and on other equipment. In this two-part study we investigated ways to make the overall visual appearance of a WZ more compatible with the needs of passers-by. The first part consisted of psychophysical tests to assess the effect on lane keeping ability when the WZ signals were ignited synchronously, as opposed to asynchronous ignition. The second part investigated the feasibility of using wireless communication to coordinate light ignition times and to create coherence among the warning lights. The feasibility of triggering the signals in sequence to create a visible pattern that is instructive...

Reservation, Scheduling, and Navigation System for a Checkpoint DRT Service

Tue, 19 Mar 2024 00:00:00 +0000

The report fully documents a prototype system that has been developed to serve Demand-Responsive Transit (DRT). The DRT service is provided by means of buses and has been proposed for deployment (as a pilot project) in Fremont, California. The service itself is to be deployed in a “hybrid” fashion; i.e., service alternates between a traditional fixed-route mode and the DRT mode from one bus trip to the next.

The report describes the prototype systems from the perspective of the system users (i.e., customers, bus drivers and administrators). Further, the report describes system configuration and deployment. Software development notes are also provided so as to document the lessons learned from our development work. In short, the works shows that reserving DRT trips and dispatching the buses can be done in automated fashion.

San Joaquin Rail Corridor Crossing Survey

Tue, 19 Mar 2024 00:00:00 +0000

In this project we have accomplished three goals. First, we have merged two existing, complementary databases in an effort to produce a single database that lists all the railroad crossings, and their known properties, in the San Joaquin Rail Corridor (SJRC). Second, we have demonstrated the practicality of using video data gathered from an existing Locomotive Video Data Acquistion System (LVDAS) to search for crossing violations in order to populate a database of crossing violations, which we term “near-misses”. By this means, crossings that are particularly susceptible to violations, considered a precursor to collisions, can be identified. Third, we have demonstrated a new in-pavement crossing signal based upon LED technology, that can serve to increase safety at crossings.

Optimizing Comprehension of Changeable Message Signs (CMS)

Tue, 19 Mar 2024 00:00:00 +0000

The goal of this research was to assist the California Department of Transportation (DOT) in optimizing the message content and presentation within changeable message signs (CMS). Optimized content will improve information transfer while at the same time minimizing the likelihood of congestion owing to slowing by motorists attempting to read the message. The research was restricted to simulated signs displaying 16 characters in each of three lines, representing permanent CMS displays, or signs containing only 8 characters in each of three lines, as is the case for portable CMS displays. While all information can be contained in a single screen for the permanent signs, multiple screens are often required for the portable CMS displays. This study specifically focused on “early vision” which is distinct from “cognitive processes”. Early vision problems are those relating to the limitations of the first several stages of the visual system. An example question of early vision is...

Berkeley Highway Laboratory Project: Final Report

Tue, 19 Mar 2024 00:00:00 +0000

This document is the final report for the 2004-2005 Berkeley Highway Laboratory (BHL) Project that is part of the University of California’s PATH program and supported by the California Department of Transportation (Caltrans). The primary objectives of this project have been to operate, maintain, enhance, and conduct research on the Berkeley Highway Laboratory (BHL) detector system. The project consists of following seven major tasks.

Task 1, Macroscopic Freeway Traffic Performance Measures

Task 2, Assessment and Improvements of Detector Diagnostics

Task 3, Installation and Testing of New BHL System at CCIT,

Task 4, Maintaining and Operating the BHL Detector System,

Task 5, Preliminary Design of Portable Detector Diagnostic Tool,

Task 6, Progress Reports and Advisory Meetings

Task 7, Preparation and Submission of Final Project Report

Evaluation of PeMS to Improve the Congestion Monitoring Program

Tue, 19 Mar 2024 00:00:00 +0000

The highway congestion monitoring program (HICOMP) report is based on data from tach vehicle runs or PeMS. Research under TO 5319 compares the accuracy and cost of these two alternatives. The detailed studies described in the report lead to the following conclusions and suggestions for follow-on work:

1. In freeway sections with good quality detectors spaced at most one-half mile apart, PeMS-based estimates of the magnitude, extent and duration of congestion are incomparably more accurate than those based on tach vehicle runs.

2. Because at most four days of tach run data are used to estimate the annual congestion over a freeway segment, the error in these estimates is on the order of 25 percent. (With only one day of tach runs, which is typical, the error is 50 percent.) The error in year to year comparisons is on the order of 35 percent, and so one can have no confidence in such comparisons published in the HICOMP report.

3. Because the location and number...

Commercial Motor Vehicles' Safety - A California Perspective

Tue, 19 Mar 2024 00:00:00 +0000

This report presents the findings of an examination of commercial motor vehicle crashes in California. Initially, a review of the basic descriptive statistics associated with truck-involved crashes in California was conducted; it covered the time period between January 1995 and December 2004 based on the Statewide Incident Tracking and Reporting System (SWITRS) data base, which contains information about every single motor vehicle accident in the state reported to a law enforcement agency. In addition to examinations of the entire population of truck-involved crashes in the state over the designated period, truck-involved crashes in Los Angeles County and the San Francisco Bay Area were also investigated. The next part of the report investigated the rates of truck accidents across California to determine the risk factors involved, including exposure to truck crashes, environmental conditions and demographic factors. The investigation involves modeling crashes as a function of...

A Low-cost Wireless MeMS System for Measuring Dynamic Pavement Loads

Tue, 19 Mar 2024 00:00:00 +0000

Work done under this "Innovative Proposal" may be summarized as follows. A closed-form series solution is provided for the displacement of a pavement loaded by a truck modeled as an Euler beam with elastic foundation under a moving load. A method is developed to estimate the load based on accelerometer measurements. Lastly, it was found that the measurement system that we built was not suited for the problem at hand because the accelerometer bandwidth was too high and the system could not isolate the accelerometer from ambient noise. This led to a new measurement system design. However, that design could not be built because of the limited resources available.

Evaluation of the Bay Area Incident Response System (BAIRS)

Tue, 19 Mar 2024 00:00:00 +0000

The Bay Area Incident Response System (BAIRS) is an integrated Web and GIS based incident tracking system that provides tools to improve California’s Department of Transportation (Caltrans) incident management capabilities. Currently, BAIRS aids District 4 Maintenance respond to and track over 33,000 incidents per year throughout the San Francisco Bay area.

The report presents the findings from the evaluation of the BAIRS system based on field data on incidents and traffic conditions. Through the implementation of BAIRS, incident response and clearance times were reduced by about 15%. Incident related delays were reduced by 210,000 vehicles-hours annually. The estimated BAIRS benefit-cost ratio is 5:1 based on the incident delay savings. Other benefits that are not reflected in the benefit-cost ratio include reduced fuel consumption and mobile emissions, and improved safety and access for emergency response vehicles.

Vehicle/Driver Monitoring for Enhanced Safety of Transit Buses

Tue, 19 Mar 2024 00:00:00 +0000

This report documents the findings of the study “Vehicle/Driver Monitoring for Enhanced Safety of Transit Buses” conducted as part of the PATH project TO5400. The goal of study TO5400 is todesign and implementation of a reliable vehicle/driver monitoring system with aim to enhance driving safety of transit buses.

The main objectives of the project are: (1) to identify a simply model that best describes the driving patterns of human drivers, and (2) to develop an algorithm which can generate warning messages when there is a provision of danger.

In this study, it is assumed that the driver sets the angle of the steering wheel in response to the lateral deviation of the vehicle from the center line of the road and/or the road curvature ahead of the vehicle which he/she infers from the visual perception. It is also assumed that the dynamic relationship between the lateral deviation and the road curvature (i.e. the inputs to the driver) and the steering angle (i.e. the...

Model of Human Vehicle Driving- A Predictive Nonlinear Optimization Approach

Tue, 19 Mar 2024 00:00:00 +0000

When driving a vehicle the human acts as a controller in a highly dynamic environment. Thus human behavior in that control loop has to a large extent been described using control theoretical methodology. We develop a driver model, in which driving is seen as a model predictive control task in such away that the driver accumulates knowledge about his/her vehicle‘s handling properties. He/she builds a model out of that knowledge and uses it to predict the vehicle’s future reactions on his/her control inputs. The human’s behavioral optimization is reflected in the driver model by using that prediction model in order to optimize control inputs such, that a set of criteria, which reflect human well-being, are minimized. Prediction models and criteria depend on the current driving situation and on personal driver preferences. The principal properties of the driver model are discussed using very simple standard maneuvers like driving straight and cornering under different preferences....

Fault Diagnosis and Safety Design of Automated Steering Controller and Electronic Control Unit (ECU) for Steering Actuator

Tue, 19 Mar 2024 00:00:00 +0000

This final reports the fault analysis of precision docking system and safety design of the safety critical elements for precision docking system. The report includes three Parts, including:

Part I provides a description of the Precision Docking System and reports analysis for fault diagnosis and safety design of automated steering controller and Electronic Control Unit (ECU) for steering actuator. It also reports a demonstration PATH conducted during the National Intelligent Vehicle Initiative demonstration organized by the US Department of Transportation Joint Program Office.

Part II report an analysis and design for a reliable direct drive for the steering wheel column of buses.

Part III reports power system reliability.

Study of Integrated Corridor Management for San Francisco Bay Area I-880 Corridor

Tue, 19 Mar 2024 00:00:00 +0000

This document summarizes the efforts by the San Francisco Bay Area ICM team to develop the concept of operation, data needs and performance requirements for an Integrated Corridor management System for I-880 Corridor. Although the transportation management systems at the Bay Area are consistent with the regional ITS plans, these management systems are less integrated. It is believed that higher lebel of intergration among freeway and arterial systems, transit systems with consideration of all transportation needs demands in the region will greatly enhance and improve the efficiency and productivity of all individual systems. ICM benefits include, to name a few, enhanced ability of the partner agencies to provide true integration of multiple operational components of the corridor, better management of non-recurrent congestion caused by major incidents, unexpected high travel demand, and major construction and maintenance activities by allowing the full capacity of the corridor...

Bus Lanes/Bus Rapid Transit Systems on Highways: Review of the Literature

Mon, 18 Mar 2024 00:00:00 +0000

This report documents a review of the literature illustrated by examples of bus rapid transit systems practice implemented on conventional highways. By conventional highways we mean arterials, freeways and busways, which are frequently referred to, respectively, as on-street and off-street bus service options. On-street bus facilities have widespread applicability because of their relatively low costs, ease of implementation, and opportunities for incremental deployment. For on-street facilities, numerous implementation options exist depending on the placement of the bus lane (curb or median), direction of flow (normal or contra-flow), mix of traffic (buses only (dedicated bus lanes), buses and taxis, buses and goods delivery vehicles, or mixed traffic flow with automobiles), and traffic controls (turn controls, parking, loading and unloading of commercial motor vehicles, and signalization). Off-street bus rapid transit running ways, however, require higher investments in land...

Development of Requirement Specifications for Transit Frontal Collision Warning System

Mon, 18 Mar 2024 00:00:00 +0000

This report documents the development of a preliminary specification for a transit bus frontal collision warning system, based on a system engineering approach. The research efforts included: 1) a literature review, 2) detailed analyses of the five-year safety records of a group of California transit properties to identify the causes of their safety problems, 3) an in-depth data collection and analysis from instrumented buses serving San Mateo County, CA, and 4) development and testing of three generations of transit bus frontal collision warning systems, incorporating enhancements to meet the needs identified by the bus drivers using the prototype systems. The analyses of the safety records and the combination of video and engineering data from the instrumented buses provide a uniquely rich pool of data for diagnosing transit bus safety challenges. The prototype warning systems incorporated innovations in signal processing to ensure that warnings are issued with high reliability...

Are Public-Private Partnerships a Good Choice for U.S. Highways? A Review of the Literature

Mon, 18 Mar 2024 00:00:00 +0000

In light of chronic funding shortfalls and waxing highway construction and maintenance demands, public private partnerships (PPPs) (often though not always in conjunction with road pricing) have been garnering increasing attention from government officials in the U.S. and abroad. Despite many strongly-held opinions on PPPs – both pro and con – systematic evaluations of their efficiency, effectiveness, equity, and feasibility are all too rare.

This paper is the first part of a research project that aims to rectify this shortage of careful, evenhanded, and rigorous analyses of PPPs by drawing on the research literature to develop a comprehensive PPP evaluation framework. Drawing on a careful and extensive review of the research literature, we (1) present the often misunderstood economic properties of highway and road infrastructure, (2) outline the rationales governments cite for engaging in PPPs, (3) review the various types of applicable PPP arrangements, and (4) describe...

EDAPTS Test Deployment: System Installation and Technical Review Report

Mon, 18 Mar 2024 00:00:00 +0000

The California Department of Transportation (Caltrans) and the Federal Transit Administration (FTA) embarked on a research program entitled “Efficient Deployment of Advanced Public Transportation Systems” (EDAPTS) in the late 1990’s. The Bronco Express EDAPTS Stage 5 Deployment Demonstrationproject at California State Polytechnic University, Pomona (Cal Poly Pomona) is an integral part of this program. Its objective is to go through the procurement and deployment process of a low cost Intelligent Transportation Systems (ITS) solution to determine if the EDAPTS concepts are optimized for small transit agencies and if they can be successfully transitioned to the commercial marketplace.

This report documents the installation, verification, and validation steps associated with the Bronco Express EDAPTS Demonstration project. It identifies and summarizes procedures that are effective in installing and testing a lower-cost ITS system and provides a practical methodology for...

Institutional Issues and Arrangements in Interoperable Transit Smart Card Systems: A Review of the Literature on California, United States, and International Systems

Mon, 18 Mar 2024 00:00:00 +0000

Many public transit agencies in California have implemented or are in the process of implementing smart card fare collection systems. Smart cards can provide riders with a convenient fare medium that eliminates the need for exact change, and offers riders one fare card that can be used across multiple modes, operators, and even different jurisdictions. For transit operators, smart cards can minimize fare fraud and pilfering, reduce operating and maintenance costs, speed up boarding times, and enhance data collection for planning purposes. One important objective of transportation planning in California is to increase transit ridership, and smart cards are widely viewed as a way to make transit use more convenient and appealing.

To date, transit agencies in California have begun to implement smart card technologies either as stand-alone systems that are incapable of interoperability with other systems, or as “regional” partner schemas where multiple agencies serving contiguous...

Cal Poly Pomona EDAPTS Test Deployment Operations Description Version 6.0

Mon, 18 Mar 2024 00:00:00 +0000

This report documents the outcomes of the February 6, 2007 workshop. It presents the most valued system characteristics of the Bronco Express EDAPTS system through the use of scored operational scenarios. The operational scenarios included in this report are down selected from those described in the initial release (V3.0) of the Operations Description report. The Advisory Panel members considered only scenarios with medium or high priority to be worthy of final consideration as deployable elements. These selected scenarios will allow the researchers to have an overall understanding of how the system will need to function in daily activities, better characterize the benefits that will be realized, and define any limitations that will have to be accommodated when the system is actually implemented.

This report is intended to communicate overall quantitative and qualitative EDAPTS system characteristics to users, developers, integrators, dispatchers, administrative staff...

Weaving Analysis, Evaluation and Refinement

Fri, 15 Mar 2024 00:00:00 +0000

Weaving sections are common design elements on freeway facilities such as near ramps and freeway to-freeway connectors. When the traffic demands exceed the capacity at weaving areas congestion may occur, which affects the operation of the entire freeway section. Traffic operational problems also may exist at weaving areas even when traffic demands are less than capacity because of the complexity of vehicle interactions, resulting in poor level of service (LOS) and potential safety problems. Existing procedures for the design and analysis of freeway weaving sections have several shortcomings, and their practical application often produces inconsistent results.

This report describes the work performed under PATH Task Order 6304. The objective of the study was to evaluate the existing weaving analysis procedures to determine under which conditions the “best available” tools are most effective. The HCM2000, Leisch and Level D methods were evaluated using field data from 36...

Development of Hardware in the Loop Simulation and Paramics/VS-PLUS Integration

Fri, 15 Mar 2024 00:00:00 +0000

The report describes three research efforts carried out under a project titled “Development of Hardware-in-the-Loop (HiL) Simulation and Paramics/VS-PLUS Integration” sponsored by the California Department of Transportation (Caltrans) under Task Order 5311. The first effort developed and evaluated traffic signal optimization with Hardware-in-the-Loop Simulation (HiLS), using the NIATT Controller Interface Device (CID) manufactured by McCain Traffic Supply to provide real-time linkage between the Paramics microscopic simulation and a NEMA TS1 controller. An adaptive control system incorporated the traffic flow prediction model to predict the traffic flows from the surrounding intersections, and an online signal optimization model was used to obtain the signal timing plan for the subsequent cycle, based on the traffic flows predicted in the previous cycle. The performance of the proposed adaptive control system was evaluated through a case study in which HiLS is applied to a small...

Field Testing of RFID for Parking Management

Fri, 15 Mar 2024 00:00:00 +0000

This report summarizes a field evaluation project involving investigation of the feasibility ofusing RFID technology to record vehicle and traveler activities at transit parking lots and at the station entrance. The report presents the field test results collected at a Bay Area Rapid Transit (BART) station, the analyses on the reliability RFID technologies for correlating parking events to station entries and observations on whether travelers accept RFID concept. The study concluded that, under certain design constraints, RFID can be utilized for parking management applications. The report also made recommendations for further investigations.

Evaluation of Portable Automated Data Collection Technologies: Interim Report, Work Accomplished During Fiscal Year 2005-2006

Thu, 14 Mar 2024 00:00:00 +0000

This report documents work accomplished during Fiscal Year 2005-2006 as a part of a research project entitled “Evaluation of Portable Automated Data Collection Technologies.” Major activities during this period included a literature survey, surveys of potential users and vendors, preliminary evaluation of portable data collection technologies to select candidate systems for demonstration, and development of demonstration plans. There is demand for portable automated data collection systems for uses related to planning, traffic operations, traffic census, and traffic surveillance functions. Potential users are interested in volume count, speed, occupancy, travel time, vehicle-length classification, and axle-based vehicle classification data. Potential uses require systems to remain installed from a few hours up to several years. Potential users want systems that minimize traffic disruption and exposure of crews to traffic, are “plug-and-play,” have IP-addressable communications...

Evaluating the Costs and Benefits of Transit Smart Cards

Thu, 14 Mar 2024 00:00:00 +0000

Smart cards are gaining momentum as transit agencies across the country have been implementing them as a fare medium. Smart cards hold the promise of revolutionizing the way riders use transit, and how transit systems operate. But in order to adopt smart cards, transit agencies must purchase new equipment and upgrade their entire fare collection system – a very expensive process. In addition, many of the oft-touted benefits of smart cards are vague, and it is not at all certain if they are worth the high cost of implementation.

This study examines how transportation agencies in three metropolitan areas evaluated smart card systems – the only three major transit smart card cost/benefit analysis studies that we found in the U.S. by the date of data collection. In addition to these three studies, we also reviewed other less extensive analyses that only partially address issues associated with the implementation of smart card technologies as transit fare media. In reviewing...

GPS/GIS Technologies for Traffic Surveillance and Management: A Testbed Implementation Study

Thu, 14 Mar 2024 00:00:00 +0000

The fundamental principle of intelligent transportation systems is to match the complexity of travel demands with advanced supply-side analysis, evaluation, management, and control strategies. A fundamental limitation is the lack of basic knowledge of travel demands at the network level. Modeling and sensor technology is primarily limited to aggregate parameters or micro-simulations based on aggregate distributions of behavior. Global Positioning Systems (GPS) are one of several available technologies which allow individual vehicle trajectories to be recorded and analyzed. Potential applications of GPS which are relevant to the ATMS Testbed are implementation in probe vehicles to deliver real-time performance data to complement loop and other sensor data and implementation in vehicles from sampled households to record route choice behavior. A flexible GPS-based data collection unit has been designed which incorporates GPS, data logging capabilities, two-way wireless communications,...

Rest Areas – Reducing Accidents Involving Driver Fatigue

Thu, 14 Mar 2024 00:00:00 +0000

Rest areas are a countermeasure for fatigue; what role do they play in fatigue-related freeway collisions? The present study spatially evaluates fatigue collisions. In California, of 2,203,789 highway collisions recorded between 1995 and 2005, fatigue collisions accounted for 1.3% (‘strict’ definition of fatigue) and 9.7% (‘expanded’ definition). Collisions in the vicinity of rest areas were investigated using two different approaches: 1. 10-miles up/downstream of rest areas 2. Distance traveled from rest areas

Sample t-tests indicated that both fatigue and non-fatigue collisions decreased statistically significantly downstream of rest areas. Collisions due to fatigue tended to decrease immediately downstream of rest areas, then climbed after about 30 miles from rest areas, while non-fatigue collisions remained the same. Binomial tests confirmed that the percentage of fatigue collisions further than 30 miles from rest areas was significantly higher.

The study also...

Highway Traffic Data Sensitivity Analysis

Thu, 14 Mar 2024 00:00:00 +0000

This report is divided into two parts:

•Part I - Highway Traffic Data Sensitivity Analysis in Systems Approach. This work has been conducted by Dr. Xiao-Yun Lu at California PATH, U. C. Berkeley.

•Part II - Empirical and Analytical Results for Sensitivity to Loop Station Spacing. This work has been conducted by Benjamin Coifman in Civil Engineering, Ohio State University.

Since the aspects of the problem considered and approaches adopted by the two are different, it is thus necessary to separate the report into two parts. Each part is self-content.

Pedestrian and Bicycle Safety Evaluation in a SMART Corridor

Thu, 14 Mar 2024 00:00:00 +0000

The San Pablo/I-80 corridor is a “SMART” transportation corridor that extends about 20 miles along the eastern shore of the San Francisco Bay. The corridor uses Intelligent Transportation System (ITS) technologies to increase and enhance transportation mobility.

The goal of the SMART Corridor Plan was to improve vehicle mobility throughout the corridor. Since the plan focused almost exclusively on vehicular traffic, achieving these goals has the potential to raise the risk of injury to pedestrians and bicyclists without thorough analysis of the overall effects of the SMART corridor implementation.

This study identifies and describes multiple factors that may affect the behavior of pedestrians, bicyclists and drivers along the corridor. This report focuses on findings for the Berkeley sector.

The evaluation utilized multiple types of data collection including vehicle counts, field observations, field inspections, and collision data. Researchers inspected the...

An Assessment of Opportunities for Bus Rapid Transit in the San Francisco Bay Area

Thu, 14 Mar 2024 00:00:00 +0000

This report presents the findings from an investigation of opportunities to implement bus rapid transit systems in the San Francisco Bay Area with a focus on bus transit routes that travel on the state’s highway system. A primary component of this project has been the consideration of inter-connectivity and regional aspects of bus rapid transit systems deployment in the Bay Area. We examined approximately 200 bus transit routes in the Bay Area that lie on the state highway system from which five routes were identified as likely candidates for bus rapid transit implementation. Two of the five routes ─ VTA’s Line 22 and SamTrans’ Lines 390/391 ─ were selected for follow-up case study analysis because they involve bus routes on the same roadway, SR 82, which includes not only multi-jurisdictional issues by including two counties and numerous local cities, but also two transit properties making this selection uniquely qualified to consider inter-connectivity and regional aspects...

The AHS/Street Interface; Effects of Capacity Concentration on System Performance: Phase 1 Final Report

Thu, 14 Mar 2024 00:00:00 +0000

This report provides Phase 1 results for MOU 386, “The AHS/Street Interface, Effects of Capacity Concentration on System Performance.” Additional results from this project can be found in PATH Working Paper 2000-26. Within this paper, strategic issues in Automated Highway Interface design are discussed, including creation of interface components and design alternatives, with emphasis on interchange separation and highway orientation. The report also discusses land use issues associated with interchange construction.

A Comparative Safety Study of Limited versus Continuous Access High Occupancy Vehicle (HOV) Facilities

Thu, 14 Mar 2024 00:00:00 +0000

The report summarizes the findings from comparative studies of safety performance between two different types of High Occupancy Vehicle (HOV) facilities in California - continuous access versus limited access. The findings show that HOV facilities with limited access offer no safety advantages over those with continuous access, whether measured by percentage of collisions, collisions per mile, collisions per VMT, or collision severity. As part of the present research, the authors investigated the relationship between HOV design features and safety performance of HOV facilities. One key design feature is shoulder/total width. The findings indicate that maintaining adequate shoulder and total width is essential, and a quantitative estimate for the relationship between shoulder and total width versus safety performance of HOV lanes is provided. Additionally, findings from investigating other influential factors on safety performance of HOV facilities, including design features of...

Event-based ATIS: Practical Implementation and Evaluation of Optimized Strategies

Thu, 14 Mar 2024 00:00:00 +0000

This project further adapt and enhance the previous research of relevance to event-based Advanced Traveler Information Systems (ATIS) and implement the algorithms for traffic management in Anaheim. This study is also answering some basic questions in ATIS implementation associated with routing strategies, driver’s compliance and network performance. This research develops algorithms for static and dynamic optimal Changeable Message Signs (CMS). The optimized CMS schemes are based on performance evaluations using a traffic simulation-based evaluation model, DYNASMART (Dynamic Network Assignment Simulation Model for Advanced Road Telematics). Performance of ATIS depends on drivers’ compliance behavior, and the compliance issue is addressed in this research. This study develops a framework of driver’s compliance model, and incorporates it into the evaluation framework. The model includes inherent value of guidance system, and the value is analyzed via day-to-day update approach....

Relationships Among Urban Freeway Accidents, Traffic Flow, Weather, and Lighting Conditions

Thu, 14 Mar 2024 00:00:00 +0000

Linear and nonlinear multivariate statistical analyses are applied to determine how the types of accidents that occur on heavily used freeways in Southern California are related both to the flow of traffic and to weather and ambient lighting conditions. Traffic flow is measured in terms of time series of 30-second observations from inductive loop detectors in the vicinity of the accident prior to the time of its occurrence. Results indicate that the type of collision is strongly related to median traffic speed and to temporal variations in speed in the left and interior lanes. Hit-object collisions and collisions involving multiple vehicles that are associated with lane-change maneuvers are more likely to occur on wet roads, while rear-end collisions are more likely to occur on dry roads during daylight. Controlling for weather and lighting conditions, there is evidence that accident severity is influenced more by volume than by speed.

Commercial Vehicle Parking in California: Exploratory Evaluation of the Problem and Solutions

Thu, 14 Mar 2024 00:00:00 +0000

California is home to major international ports in Long Beach, Los Angeles, and Oakland, as well as the second largest border crossing between Mexico and the U.S. California’s highways are critical commercial links from these ports of entry to the nation and carry more commercial vehicle truck traffic than any other state in the U.S. Given the high volume of truck travel in California, it is not surprising that there is a serious shortage of truck parking in the state. This shortage negatively impacts economic productivity, roadway safety, air quality, and public health. This report begins with a summary of the relevant legislation history on truck parking in the U.S. Next, the shortage of truck parking in California and its impact on congestion, safety, air quality, public health, and the trucking industry’s productivity is presented. A summary of lessons learned, from stakeholder interviews, recent surveys of truck drivers, and parking guidance information for autos, are presented...

Bicycle Detection and Operational Concept at Signalized Intersections

Thu, 14 Mar 2024 00:00:00 +0000

In support of efforts to improve traffic signal timing to accommodate the needs of bicyclists, observations have been made of the timing of bicyclists’ intersection crossing maneuvers. Video recordings were made of bicyclists’ crossings and the video images were processed to extract the bicyclists’ trajectories. These were synchronized with video images of the traffic signals so that the timing of the bicyclists’ maneuvers could be determined relative to the signal phase. The processed data have yielded cumulative distributions of the crossing speeds of bicyclists who did not have to stop at the intersection and the start-up times and final crossing speeds of the bicyclists who had to cross from a standing start. A unique feature of these data is the timing information relative to the traffic signal, which will be essential for determining signal phase durations. The sensitivity of the bicycling performance measures to differences between the data collection sites indicates the...

Applying Safety Improvements to Fleet Vehicles

Wed, 13 Mar 2024 00:00:00 +0000

The safety of both employees and the motoring public is of paramount importance to Caltrans, resulting in a continuing effort to improve the operating vehicle fleet. The potential safety changes that are the focus of this project are those that involve safety equipment enhancement over and above the original specifications for the vehicle or outside of the scope of the original equipment design or purpose, such as rear view backup video cameras.

The motivation for this project was Division of Equipment (DOE) managers' need for an objective strategy to address safety equipment deployment issues. These include determining where equipment changes should be made, whether statewide or only in specific locations, what types of vehicles will be involved, and how the changes should be made, for example, immediately retrofitting certain vehicles or changing the specifications for future vehicles.

Neither question needs to be answered on an absolute basis; for example, it...

Commercially-off-the-Shelf (COTS) and Emerging Technologies Sensor Testing and Evaluation

Wed, 13 Mar 2024 00:00:00 +0000

This report addresses Task S of the Intersection Decision Support (IDS) project funded by Federal Highway Administration (FHWA) and Caltrans. The objective of Task S is to evaluate and select Commercially-Off-The-Shelf (COTS) and emerging technology products that could eventually be deployed at intersections as part of the IDS system. Many sensors were considered and every plausible detection technology was reviewed for this task. The emphasis was on finding sensors that detect and track vehicle movements.

This effort started with establishing a background and general guidelines for what this task was set to accomplish. Then, our hypothesis and assumptions as well as our constraints and limitations to achieve our goals were clearly defined. At last, the evaluation criteria were established.

By considering the above, a comprehensive survey was done to find the sensors and detectors that show the most promises to be included in the IDS system. This survey covered...

Assess the Trade-Offs between People Through-put and Level of Service Degradation in the Conversion of a Mixed Flow Lane to a Bus Only Lane on US 101

Wed, 13 Mar 2024 00:00:00 +0000

This report proposes a generalized process for evaluating the ridership impact and traffic impact of a bus rapid transit system. The process proposed aims at providing such evaluation at the sketch planning stage and has a specific focus on two aspects -- the ridership forecast based on the implementation of various ITS technologies and the degradation of level of service that results from converting a traffic lane into exclusive bus lane for the implementation of a bus rapid transit system. The proposed process is tested on the Van Ness Blvd site in San Francisco, California. It is also implemented as a web-based toolbox that is easily accessible.

An Evaluation of the Consequences and Effectiveness of Using Highway Changeable Message Signs for Safety Campaigns

Wed, 13 Mar 2024 00:00:00 +0000

Changeable Message Signs (CMSs), which are also called dynamic or variable message signs, are programmable signs used on highways worldwide to provide drivers with real-time information, such as traffic updates, roadwork warnings, and other traffic and safety-related information. CMSs allow motorists to take immediate action in response to information—to slow down or change routes, for example, which leads to safer driving conditions and less congestion. More recently, in California and throughout the U.S., CMSs have been used as part of public campaigns to promote roadway safety by posting messages that encourage drivers to use seat belts, not to drink and drive, and not to speed. These messages are typically displayed on CMSs during designated time periods that coincide with broader safety campaigns.

This study was sponsored by the California Department of Transportation (Caltrans) to examine the following questions about displaying safety campaign messages on CMSs:...

Commercial Motor Vehicle Inspection and Screening Stations: Evaluating Performance from the Perspective of Practitioners

Wed, 13 Mar 2024 00:00:00 +0000

This report presents the findings of a study of commercial motor vehicle inspection and screening station practices with a focus on the use of various technologies to help address problems related to safety, security, roadway infrastructure, and air quality. A review of industry literature identified the various types of inspection and screening practices that have been and are being implemented including weight and size management, on-board equipment checking, driver-related violations and cargo monitoring, credential checking, and exhaust emissions monitoring. The review also identified technologies that have been employed as part of these practices as well as an assessment of their performance. The research also involved the use of a survey of State and Provincial Departments of Transportation in North America that have implemented specific practices. Survey findings indicate that to a certain degree a more integrated and multi-practice approach is being taken; a wide array...

SPRINTER Rail: Grade Crossing/ Traffic Signal Optimization Study

Wed, 13 Mar 2024 00:00:00 +0000

The second phase of this project further investigates impacts to local traffic operations at intersections adjacent to signal preemption by SPRINTER commuter trains and comes up with countermeasures that not only minimize such impacts but also take into account the traffic signal coordination. An extended traffic signal optimization model has been developed to minimize overall traffic delays and the weighted width of “green band” along several coordinated traffic signals around the grade crossings. Based on the train’s movement detection at grade crossings and the waiting queue estimation at the end of the preemption operation, the optimized signal timings can quickly clear the queue and still maintain coordination along the corridor of interest. This study also recommends further consideration of countermeasures involving advanced train detections.

Smart Cards, Slow Deployment: Findings from Interviews with U.S. Transit Agencies

Wed, 13 Mar 2024 00:00:00 +0000

This report summarizes findings from interviews with transit officials at seven agencies in North America about smart card evaluations, expectations, and implementation. As part of the project, “Designing a Policy Framework for a Statewide Transit Smart Card System,” this report was preceded by a literature review of smart card projects and an online survey of transit agencies’ knowledge of and interest in interoperable smart card systems for fare collection. The literature review found a lot of booster-like enthusiasm for smart cards, but few studies that have rigorously evaluated smart card system benefits relative to their costs, nor have they addressed the array of institutional issues that hinder implementation. Our survey revealed that many transit agencies are in the process of considering or have already adopted smart card systems, often without clear or certain information about the costs of these systems. Prior to forming collaborations with other agencies, surveyed...

Onboard Monitoring and Reporting for Commercial Vehicle Motor Safety

Wed, 13 Mar 2024 00:00:00 +0000

This final report describes the process and product from the project, Onboard Monitoring and Reporting for Commercial Motor Vehicle Safety (OBMS), in which a prototypical suite of hardware on a Freightliner Century Class truck was developed and tested.

The OBMS suite allows for online measurement of a set of driving characteristics which are indicators of unsafe driving behavior. These characteristics include speed, following distance, lane keeping performance, safety belt use, and the use of turn signals. Feedback can be provided to the driver, either directly via real time feedback or through carrier management, to allow drivers to significantly improve their safety performance. For example, if a driver receives a report that he/she is not using his/her turn signals during lane changes, that driver can then be monitored during a follow up period to determine if feedback had corrected the deficiency. This concept would be pioneered in commercial fleets because they have...

PLANiTS: THE METHODS BASE, Model Selection and Model Integration

Wed, 13 Mar 2024 00:00:00 +0000

This paper presents some features of PLANiTS (Planning and Integration for Intelligent Transportation Systems). In particular, it discusses some functions of the Methods Base. These include representation of model chains, selection of models and data, and data transformations and aggregation. Sequences of models are represented using graph notation. Models and data are selected given the Planning Vector specification, although users may override system selections. The Methods Base features are illustrated with an example drawn from the PLANiTS prototype (version 1 .O).

Evaluation of Traffic and Environment Effects on Skid Resistance and Safety Performance of Rubberized Open-grade Asphalt Concrete

Wed, 13 Mar 2024 00:00:00 +0000

Wet pavement-related collisions represent a significant traffic safety concern, due in part to the lack of adequate friction between tire and pavement, known as skid resistance. State agencies employ a skid number (SN) system, based on a standard test procedure in which a locked wheel is towed at 40 mph and the skid number (SN40) is calculated from the measured resistance. SN40 is used as a reference value for speeds both greater than and less than 40 mph. For most Departments of Transportation (DOTs) in the nation, excluding California, pavements for which the SN40 is below 30 are deemed unacceptable and corrective actions are required.

The main objectives of this study are (1) to evaluate and analyze skid test results from the test data inventory, and (2) to identify and analyze before-and-after collision data at sites where three experimental types of pavements (Open Graded Asphalt Concrete [OGAC], Groove Pavement [GP], and Rubberized Open Graded Asphalt Concrete [R-OGAC])...

Improving Mobility Through Enhanced Transit Services: Case Studies for Transit-Taxis

Wed, 13 Mar 2024 00:00:00 +0000

This report, an interim deliverable for Task Orders 5408 and 6408: “Improving Mobility through Enhanced Transit Services”. Thus far in the study we have performed a review of the literature and conducted a small number of site-specific case studies for transit agencies in North America identified from the literature review as either currently having or in the past having had transit-taxi service implemented in their agency’s jurisdiction. We initially classified alternative concepts of transit-taxis into a typology of three service design options based on a review of the literature: 1) fixed route, 2) fixed-route with deviation, or 3) hybrid/feeder service and three operational strategies: 1) using in-house vehicles and labor, 2) contracting out services, or 3) relying on the private market to meet demand. After the literature review, we performed the transit-agency-based case studies using a question-and-answer interview style over the telephone.

Radio Frequency ID Tags to Enhance Safety

Wed, 13 Mar 2024 00:00:00 +0000

This project was originally conceived and executed to deliver a proof-of-concept of a near-term “cooperative vehicle-highway system” using a Radio Frequency Identification (RFID) tagging system to significantly improve the reliability of rear-end truck-based forward collision warning (FCW) systems. A hardware apparatus was developed but proved difficult and relatively costly to design and prototype; however, one set of RFID apparatus was delivered by our Raytheon subcontractor to PATH, then it was tested at PATH. Because of range limitations it did not perform to the extent that it could conceivably enhance FCW systems.

At the time this work was being conducted, the emergent TO 5217 dealing with Vehicle-Infrastructure Integration (VII) was beginning, and an idea – curve overspeed warning – was inspired by the generalization of “look-ahead” within this project. The work under this project, therefore, was transformed into conceiving and the start of implementing such a...

Multi-Channel Medium Access Control for Dedicated Short Range Communications

Wed, 13 Mar 2024 00:00:00 +0000

This paper describes a medium access control (MAC) protocol to enable multi-channel operation for dedicated short range communication (DSRC). In particular, we focus on the challenge of supporting potentially high-bandwidth commercial or info-tainment communications between vehicle and roadside in hotspots over several service channels, while concurrently enabling time-critical vehicle-vehicle communication for safety in a separate channel. In our architecture, within hotspots, communication is aided by one of the access points in the hotspot. This access point is designated the Coordinating Access Point (CAP). Outside hotspots, communication is for safety and is conducted in an ad-hoc fashion. The CAP protocol design is a variant of IEEE802.11 PCF, modified for multi-channel operation. The design objective is to maximize utilization of the service channel used for non-safety communication while meeting the Quality of Service (QoS) constraints of the safety communications. The...

Medium Access Control Protocol Design for Vehicle-Vehicle Safety Messages

Wed, 13 Mar 2024 00:00:00 +0000

We propose a Medium Access Control (MAC) protocol design for a vehicle to send safety messages to other vehicles. We develop a QoS model for safety messages consistent with the active safety systems literature. Each message has a range and useful lifetime. The QoS target is to have each message be received with high probability within its specified lifetime by each vehicle within its specified range. The protocol design is based on rapidly re-broadcasting each message multiple times within its lifetime in combination with the 802.11 DCF. This makes the design compatible with the emerging standards for DSRC. Six different design variations are proposed. We derive equations and develop a simulation tool to assess the performance of the designs. Using these we identify the best and most easily implemented of the designs. Design performance depends on the number of re-broadcasts, power, modulation, coding, and vehicular traffic volumes. We show that under certain assumptions on the...

Evaluation of Incorporating Hybrid Vehicle Use of HOV Lanes

Wed, 13 Mar 2024 00:00:00 +0000

This report presents a method to investigate the operational and environmental effects of the policy of allowing qualified single-occupancy hybrid vehicles to use dedicated High-Occupancy Vehicle (HOV)/carpool lanes in California.. The method combines the traditional planning method with microscopic simulation modeling. The planning method is used for demand estimation and analysis and the microscopic traffic simulation modeling method is used for accurate measures of the system. The study employs a microscopic traffic simulation model that is capable of evaluating the HOV/hybrid system and providing detailed outputs that are not available in conventional static models. The study also includes detailed emissions modeling in order to estimate accurate emissions by integrating emission models into microscopic simulation models. An important aspect of the study involves predicting future hybrid vehicle demand; hybrid demand models are developed based on consumers' automobile choice...

Toward Deployment of Adaptive Transit Signal Priority Systems

Wed, 13 Mar 2024 00:00:00 +0000

This document reports the continuous efforts conducted by California PATH Program on the development and implementation of an Adaptive Transit Signal Priority (ATSP) system. The ATSP system has three distinguished features, including: (1) providing priority to transit vehicles while making a tradeoff between bus delay savings and the impacts on the rest of the traffic, (2) utilizing existing AVL/communication system already instrumented on buses to continuously monitor bus locations and predict bus arrival times to intersections and to request signal priority, and (3) building upon closed-loop signal control systems with 170E controllers. These features allow ATSP to have potential for wide-scale implementation. This report describes the development of ATSP algorithms, the field testing results of the prototype ATSP system and the feasibility analysis for utilizing existing transit communication for ATSP.

Driver/Pedestrian Behavior at Marked and Unmarked Crosswalks in the Tahoe Basin

Wed, 13 Mar 2024 00:00:00 +0000

For more than thirty years, pedestrian safety studies have considered pedestrian-vehicle collision history and pedestrian and driver behavior at marked and unmarked crosswalks at uncontrolled crossings. From 2005-2007, the UC Berkeley Traffic Safety Center, in a study funded by the California Department of Transportation (Caltrans), focused on developing a better understanding of driver and pedestrian behavior and safety in both marked and unmarked crosswalks in an effort to recommend more informed crosswalk policies. As a part of these efforts, a 2007 paper, “The Marked Crosswalk Dilemma: Uncovering Some Missing Links in a 35-Year Debate” was designed to fill key gaps in the literature by analyzing pedestrian and driver behavior and knowledge of right-of-way laws regarding marked and unmarked crosswalks throughout the Bay Area.

The UC Berkeley study, as with most previous studies, focused on urban or suburban areas where the driver characteristics do not change significantly...

Vehicle Sorting for Platoon Formation: Impacts on Highway Entry and Throughput

Wed, 13 Mar 2024 00:00:00 +0000

This paper develops and evaluates strategies for organizing vehicles into platoons, with the objective of maximizing the distance that platoons stay intact. Fundamentally, this entails grouping vehicles according to their destination. We evaluate various strategies in which vehicles are sorted on entrance ramps, with respect to platoon sizes, throughput and queueing characteristics.

Cooperative Adaptive Cruise Control: Testing Drivers’ Choices of Following Distances

Wed, 13 Mar 2024 00:00:00 +0000

Development of a Modeling Framework for Analyzing Improvements in Intermodal Connectivity at California Airports

Wed, 13 Mar 2024 00:00:00 +0000

This report has been prepared as part of a research project developing a combined quantitative and qualitative approach to planning for improved intermodal connectivity at California airports. The quantitative approach involves the development of an Intermodal Airport Ground Access Planning Tool (IAPT) that combines an air passenger mode choice model, a model of transportation provider behavior and a traffic network analysis model. The qualitative approach will be used to enhance the quantitative analysis to account for those factors which are difficult to quantify and to provide recommended policy and planning guidelines. This report represents a continuation of the previously submitted Working Paper, so that together they describe the main work conducted in the first year of the project. This report summarizes the work reported in the Working Paper in Chapter 3: Opportunities for Improved Intermodal Connectivity at California Airports. This report concentrates on the modeling...

Productivity and Cost-Effectiveness of Demand Responsive Transit Systems

Tue, 12 Mar 2024 00:00:00 +0000

We study the impact on productivity of specific operating practices currently used by demand responsive transit (DRT) providers. We investigate the effect of using a zoning vs. a no-zoning strategy and time-window settings on performance measures such as total trip miles, deadhead miles and fleet size. It is difficult to establish closed form expressions to assess the impact on the performance measures of a specific zoning practice or time-window setting for a real transportation network. Thus, we conduct this study through a simulation model of the operations of DRT providers on a network based on data for DRT service in Los Angeles County. However, the methodology is quite general and applicable to any other service area. Our results suggest the existence of linear relationships between operating practices and performance measures. In particular we observe that for each minute increase in time-window size the service saves approximately 2 vehicles and 260 miles driven and that...

A Paramics Plugin for Actuated Signal Control and First Generation UTCS

Tue, 12 Mar 2024 00:00:00 +0000

This report serves as a user manual for a plugin developed under the Paramics API for simulating standard surface street traffic controllers. The strategies included are time-of-day, actuated signal control, traffic responsive, and traffic responsive with critical intersection control.

Preparing the Way for Vehicle-Infrastructure Integration

Tue, 12 Mar 2024 00:00:00 +0000

Vehicle-Infrastructure Integration (VII) is one of the most important new national programs within the field of ITS, but until now it has been treated at the federal level as a deployment-oriented activity, without significant research elements. This report identifies some key research issues that need to be investigated in support of VII, in order to ensure that the VII concept and designs are as efficient and effective as possible and in order to produce the essential knowledge base that public agencies throughout the country can rely upon to make well-informed decisions about participating in the deployment of VII.

Institutional Challenges to the Development and Deployment of ITS/ATS Systems in California

Tue, 12 Mar 2024 00:00:00 +0000

This report provides an overview of the key institutional challenges that could affect the development and deployment of Intelligent Transportation Systems/Advanced Transportation Systems (ITWATS) technologies in California. The findings of the study are based on a series of in-depth interviews and review of research related to “non-technical” constraints both in California and at the national level. Based on this review, the study outlines three core areas that require attention: research collaboration--which focuses on public/private partnerships in the development of new technologies; regional management--which focuses on the coordination of metropolitan planning and deployment of ITS/ATS systems, and stakeholder acceptance--which focuses on the institutional and user acceptance needed for ITS/ATS systems to be successful. After describing how each of these three areas are manifest in California, the report then provides an inventory of relevant lessons that could be learned...

Cooperative Collision Warning Systems: Concept Definition and Experimental Implementation

Tue, 12 Mar 2024 00:00:00 +0000

The concept of cooperative collision warning (CCW) systems is introduced and explained, followed by presentation of experimental results showing the performance of a first prototype CCW system. The CCW concept provides warnings or situation awareness displays to drivers based on information about the motions of neighboring vehicles obtained by wireless communications from those vehicles, without use of any ranging sensors. This has the advantages of a potentially inexpensive complement of onboard vehicle equipment (compared to ranging sensors that could provide 360 degree coverage), as well as providing information from vehicles that may be occluded from direct line of sight to the approaching vehicle. The CCW concept has been tested on a fleet of five prototype vehicles, supporting a variety of safety services (forward collision warning, blind spot and lane change situation awareness and several modes of intersection threat assessment). The performance of the vehicle position...

Design of a Demand-Responsive Transit System

Tue, 12 Mar 2024 00:00:00 +0000

This research investigates the feasibility of offering demand-responsive transit (DRT) service to the general public in situations of low demand density. The study region is AC Transit District 2 which consists of the cities of Fremont and Newark, California.

We developed a methodology to evaluate operating efficiencies of existing bus lines and line segments, and identified areas suitable for DRT service based on year 2001 data. We proposed an alternating strategy of checkpoint DRT service and compared it to other strategies. The report also described the schema for an automated reservation and scheduling system.

Our initial findings are: the service cuts and route changes implemented by AC Transit district 2 after 2001 largely concur with our analysis of the 2001 system; by making very limited additional changes to the fixed routes and using the proposed checkpoint service, AC Transit could have a net savings of 2-3 buses; and finally, this service offers considerable...

Developing Operating Rules and Simulating Performance for One-dedicated-lane Bus Rapid Transit/Light Rail System

Tue, 12 Mar 2024 00:00:00 +0000

Caltrans has recently funded a project, through the Mineta Transportation Institute (MTI) at San Jose State University, about geometric and performance feasibility of using virtually only one dedicated but dynamically reversible lane to provide two-way Bus Rapid Transit (BRT) or light-rail services at the same or similar service levels as those achievable with two dedicated lanes, along the median of a busy commute corridor with at-grade crossings and regular provision of left-turn lanes. This project extended that deterministic performance study in four complementary directions. We (i) developed two episodes of simulation/animation to facilitate understanding key ideas of the concept, (ii) addressed the “backward-compatibility” issue, (iii) developed speed control rules to absorb the impact of the stochastic demand (and the different distances between pairs of neighboring stops) on the performance of a closed system, and (iv) developed speed control rules and transit-signal-priority...

Factors Influencing Productivity and Operating Cost of Demand Responsive Transit

Tue, 12 Mar 2024 00:00:00 +0000

Since the enactment of the Americans with with Disabilities Act, in 1991, operating expenses for Demand Responsive Transit have more than doubled as demand for this mandated service has expanded. Many advanced technologies and management practices have been proposed and implemented to improve the efficiency of the service; but, evidence for the effectiveness of these actions has been based upon projections or small pilot studies. We present the results of a nationwide study involving 67 large transit agencies. We evaluate the impact of implemented technologies and practices upon productivity and operating cost.

Identifying Density-Flow Relations on Arterial Surface Streets

Tue, 12 Mar 2024 00:00:00 +0000

A simple car-following rule was verified by studying vehicles discharging from long queues at signalized intersections. These observations indicated that the time-space trajectory of a jth vehicle discharging on a homogeneous intersection approach was essentially the same as the j−1th vehicle except for a translation in space and time. This is in agreement with a simplified theory proposed by G.F. Newell. The finding indicates that the congested branch of a density-flow curve is linear in form.