This work illustrates that false alarms are likely to have significant frequencies as well as detrimental influence on the effectiveness of human-machine warning systems. Several factors are responsible for false alarm materialization, including the need to predict uncertain conditions in the future, variability of human perception, and low a priori probabilities of traffic collisions. The effect of false alarms on human trust in warning systems and on credibility of warnings could be considerable even for low false alarm rates. One way to decrease false alarm rates would be to focus on predicting possible conflicts, which are much more probable than actual collisions (thus increasing a priori probabilities). One of the suggested future research directions is to assess directly what different individuals will view as being a false alarm. In the majority of existing studies, the researchers defined this outcome. It is possible that people will change their behavior based on their perception of false alarms rather than on a researcher's definition of them.

This study explores the association between vehicle occupancy and a driver’s risk of causing a fatal crash, not wearing a seatbelt, and using alcohol. The survey population is the set of drivers represented in the Fatal Analysis Reporting System (FARS) (years 1992 to 2002). The independent variables are driver age, driver gender, passenger age, passenger gender, and vehicle occupancy. The outcome variables are whether the driver was at fault in causing the fatal crash, whether the driver wore a seatbelt, and whether the driver had been using alcohol. For male teenager drivers, driving with teenage passengers correlated with an increase risk of causing a crash. For all female drivers, and for male drivers over age 40, passenger presence correlated with a reduced risk of causing a fatal crash. Drivers age 15 to 30 were less likely to wear a seatbelt when passengers were present, than when driving solo. Drivers age 50 and above had higher seatbelt use rates when passengers were present. This protective effect of passengers was stronger for male drivers than female drivers, and for male drivers the effect increased by age. Drivers age 15-34 accompanied by passengers were more likely to have consumed alcohol than solo drivers of the same age group. These results offer an interesting perspective for research in the area of driver distraction, and update current knowledge on older drivers and the role of seatbelt and alcohol awareness.

The focus of this study is to quantify the sufficiency of “Flashing Don’t Walk” (FDW) intervals at signalized pedestrian crossings in the San Pablo Avenue (SPA) corridor in Northern California. Our goal is to determine if pedestrian signal intervals on the SPA corridor can be optimized in a way that makes the pedestrian crossing environment safer and more comfortable for all pedestrians without diminishing vehicular throughput. This study provides a corridor-wide as well as a city-by-city assessment of FDW intervals on the SPA corridor. We suggest a possible tool to assist traffic control jurisdictions in prioritizing intersections that may require adjustments of timing to pedestrian signals. The findings provide the agencies participating in the “SMART” corridor program a means to evaluate an aspect of pedestrian safety and comfort that has likely been adversely affected by placing a high priority on vehicular traffic through the corridor, without sufficiently considering pedestrian traffic.

The present study evaluated the effect of impactable signs that used the yield-symbol as approved by the National Committee on Uniform Traffic Control Devices (NCUTCD) in the 2003 Manual of Uniform Traffic Control Devices (MUTCD). Impactable yield signs are low- costsignsconstructed of flexible material. The signs wereinstalled in the medians adjacent to crosswalks at selected non-signalized intersections to instruct drivers to yield the right-of-way to pedestrians. This paperexamines the effect on safety characteristics of the intersections of these signs at three stop-sign controlled intersections in San Francisco over two follow up periods. Since these signs were installed recently, there were no post-installation crash data for comparison with the pre-installation crash data.As such, surrogate measures, including (a) driver yielding behavior, (b) conflicts among drivers and pedestrians crossing the intersection, (c) waiting time for pedestrians, and (d) time taken by pedestrians to cross a given crosswalk were documented. Previous studies have indicated that impactable yield signs are effective in increasing the rate of drivers yielding to pedestrians. Video recordings were taken at the intersection pre- and post-installation to observe any changes in behavior. Analyses of these recordings yielded data for baselineand the first and second follow-up periods respectively. Testing the first and second follow-up data against the baseline data reveal that, a substantial increasein yielding behavior by drivers occurred immediately after installationas well as during the second follow-up period. No significant effect was observed in any other variables.

This paper describes an innovative pedestrian modeling technique known as Space Syntax, which was used to create estimates of pedestrian volumes for the city of Oakland, California. These estimates were used to calculate pedestrian exposure rates and to create a Relative Risk Index for the city’s first pedestrian master plan. A major challenge facing planners, transportation engineers, and pedestrian-safety advocates is the lack of detailed and high quality pedestrian-exposure data. Exposure is defined as the rate of contact with a potentially harmful agent or event. Pedestrian exposure is therefore defined as the rate of pedestrian contact with potentially harmfully situations involving moving vehicles (e.g., crossing an intersection). Pedestrian risk is defined as the probability that a pedestrian-vehicle collision will occur, based on the rate of exposure. To estimate exposure, pedestrian volume measurements must be made, but such measurements not easily available. In the absence of accurate exposure data, pedestrian-safety decisions are often made by estimation, rules of thumb, or political influence, resulting in mixed and potentially less effective outcomes. This paper also explores the value of the Space Syntax volume-modeling approach for generating estimates of pedestrian exposure, using the City of Oakland as a case study. It discusses the method’s theoretical background, data requirements, implementation, and results. The author suggests that the output of the model - city-wide pedestrian volume estimates - is useful to pedestrians, planners and transportation engineers, and he discusses the value of the pedestrian-exposure concept for the planning professional.

This paper examines three types of pedestrian volume models in light of their usefulness for estimating pedestrian exposure for pedestrian safety research. The need for pedestrian flow data as part of pedestrian exposure and safety analysis is outlined, and the background of each type of model is discussed. It then selects the space syntax network analysis model to estimate pedestrian volumes for the city of Boston, Massachusetts. It was found that the model was able to accurately predict pedestrian flows (r-squared 0.81, p-value < 0.0001) after incorporating distance to transit stops and major tourist attractions. These findings suggest that in addition to estimating pedestrian volumes in geographic locations where data is not available, pedestrian volume modeling can also be useful for estimating pedestrian volumes in future conditions. Planninimplications are discussed, as are directions for future research.

The Intersection Decision Support (IDS) Project is designed to reduce crossing-path (CP) crashes at intersections by providing crucial information to drivers that would help them avoid such crashes. Over the past decade, researchers have used the General Estimates System (GES, a representative sample of police-reported crashes in the US) and other data sources to develop a taxonomy of CP crashes and pre-crash scenarios as groundwork for crash-prevention efforts. The current study builds on and extends prior work by constructing a taxonomy of CP crashes using data from the 2000 GES and identifying potential corresponding IDS countermeasures. Analyses differ from previously published analyses in that traffic control device data was available at the vehicle level, and not just at the crash level. This allowed more detailed study of crashes by traffic control device. Findings included documentation that crashes at intersections represent a very high percentage of all U.S. crashes, making intersections relatively high-risk areas compared to other roadway segments. Also, CP crashes constituted a substantial portion of total crashes in the US, including 25% of all crashes and about 45% of crashes at intersections. Patterns of CP crashes differed substantially by type of intersection (defined by traffic control device), and these differences in crash patterns reflected varied underlying causal factors that required tailored IDS countermeasures. In addition, CP collisions at intersections took place at moderate speeds, which is important for algorithms for warning systems. Finally, older drivers were over-represented in crossing-path collisions at intersections. IDS countermeasures will need to account for findings on intersections here and elsewhere that address driver behavior and vehicle movement and conflict.

Driver behavior at rail highway crossings has been the subject of numerous studies, most of which show that violations are relatively commonplace. The focus of this paper will be on those drivers who drive around fully descended gates. Drivers commonly misjudge the speed and distance of trains. They must make a decision about the time remaining before the train arrives based on sensory signals as well as non-sensory factors such as expectations and motivation. At a gated crossing, where drivers have been alerted to the imminent danger by lowered gates, there is more to be gained by preventing gate running, or at least making it very difficult, than by attempting to aid drivers in making a better informed decision as to whether or not there is sufficient time to clear the crossing before the train arrives. This is especially true given people’s innate inability to judge the speed of a large object coming directly at them, both because the growth in size is not linear, and because human vision underestimates the speed of large objects. Given the costs involved in closing or making a crossing impenetrable, it is worthwhile looking at other approaches that can cost effectively reduce gate-running. These include long-arm gates, medians, photo enforcement, and four-quadrant gates.

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 physical elements of each intersection and observed driver, pedestrian, and bicyclist behavior. Analysis of these data led to a typology, used to assign context-specific safety interventions, many of which involve engineering and enforcement.

The main goal is to ensure that motorists as well as pedestrians and bicyclists should have a sense that all have an equal right to travel in the area. This can be accomplished through clear and consistent signage, a distinctive crosswalk treatment, consistent lighting and other enhancements.

Implementation of the recommended countermeasures and follow up analysis are not part of this baseline study. A detailed traffic engineering analysis would be required to produce estimates of costs and benefits, and to determine priorities.