Overweight trucks traveling illegally on the California highway network cause a significant and disproportionate amount of damage to pavements. Truck traffic is expected to account for some percentage of damage to pavements, however the percentage of pavement damage caused by overweight trucks is much greater than the expected damage from measured truck traffic volume on California highways. Many of these overweight trucks travel unmonitored throughout the network and cost the taxpayers millions of dollars every year in maintenance and rehabilitation costs.

Currently, Weigh and Compliance Stations run jointly by the California Department of Transportation (Caltrans) and the California Highway Patrol (CHP) are the sole instrument used to enforce weight and other restrictions on trucks. Currently, 38 weigh stations are strategically located throughout California. When a station is open, trucks not given a bypass signal must enter the scales and have each axle weighed. Trucks not in compliance are cited. The effectiveness of these weigh stations is limited by their operating hours, the routes they can monitor, and their operating and installation costs. Moreover, these stations can cause user delays from extended queue times for trucks waiting to be weighed.

Development of a new technology known as a Virtual Weigh Station (VWS) is currently underway. The VWS utilizes weigh-in-motion (WIM) sensors, located throughout the state, as tools for weight restriction enforcement. Caltrans Division of Traffic Operations traditionally has used these WIMs to provide data about traffic loads applied to California highway pavements. As a truck passes over a WIM, the type of truck, weight of individual axles, speed, and other data are recorded and stored by the WIM. Through the use of cameras, this data can be linked to the truck license plate and/or registration number. This data can then be relayed to the enforcing authorities, at which point trucks violating weight restrictions can be cited appropriately.

This memorandum was initiated by Caltrans for the Partners for Advanced Transit and Highways (PATH) in order to explore the idea of installing VWS in California. The study included a literature survey and expert interviews, as well as an analysis of estimated pavement performance benefits from VWS. The Pavement Research Center (PRC) was asked by PATH to estimate these benefits and other pertinent pavement information concerning overweight trucks. Specific objectives were the following:

* Estimate pavement damage caused by overweight trucks on the network. * Estimate costs of this pavement damage to Caltrans. * Estimate potential savings induced by the installation of VWS.

This technical memorandum summarizes the analysis performed to evaluate the cost of the Long-Life Pavement Rehabilitation Strategies (LLPRS) program. This study is part of the effort to develop an Integrated Pavement Strategy Decision Support System to allow engineers to analyze efficient allocation of financial resources when planning pavement projects.

For this study, cost performances were analyzed for a long-life pavement project on Interstate 10 (EA 07-181304) in Pomona between the 210/57/10 interchange to Garey Avenue undercrossing.

The project studied (EA 07-181304) is a 3.4 mile segment of the San Bernardino Freeway. It was the first concrete LLPRS project constructed and incorporated the use of Fast Setting Hydraulic Cement Concrete (FSHCC). The contract was awarded to Morrison Knudsen Corporation at $15,998,000. Construction began in April 1999 and was completed at the end of July 2000.

This technical memorandum summarizes the analysis performed in evaluating Long-Life Pavement Rehabilitation Strategies (LLPRS) cost. This study is part of the effort to develop an Integrated Pavement Strategy Decision Support System to allow engineers to analyze efficient allocation of financial resources when planning pavement projects.

This study analyzed cost performances of a long-life pavement project on Interstate 80 between Nevada County (Truckee) from east of the Fireboard undercrossing to the west end of the Truckee River Bridge.

The rehabilitation project involved rehabilitation of an 11-mile stretch of I-80 (approximately 46 lane miles) between West Boca and Floriston, east of Truckee. The contract was awarded to Granite Construction Company of Watsonville; construction began April 2, 2001. The cost of the project was estimated to be $88 million, however, the final cost of the project totaled at about $99 million. The analysis performed determines the reasons for the difference between the estimated and actual costs.

This report presents the results of the study, "Pilot Project for Fixed Segmentation of the Pavement Network."

The goal of this pilot project was to study a small sample of the California Department of Transportation (Caltrans) network to determine the feasibility of expanding the pilot approach to the entire pavement network. The project's work included evaluating the effectiveness of ground penetrating radar (GPR) and limited coring for measuring pavement layer thicknesses and types, application of an algorithm for determining "fixed" segmentation of the pilot network, population of a database for the pilot network, then assessing costs of these activities.

Fixed segmentation for use in the Pavement Management System (PMS) is required to develop the capability to do pavement performance modeling, which is essential for the following pavement management tasks:

* Predicting future performance of segments of the network, and * Identifying the most cost-effective maintenance and rehabilitation (M&R) strategies based on life-cycle costs.

Pavement layer-type and thickness data are also needed to develop effective pavement performance models and to conduct effective condition surveys of composite pavements (asphalt overlays of PCC pavement). The data are also useful for project-level engineering.

Background information summarizing the experiences of several other states in using GPR for pavement work is also presented.

The pilot network consisted of a total of eight roadways: three interstate highways (I-5, I-505, and I-80), four state routes (SR-16, SR-45, SR-99, and SR-113), and one U.S. highway (US-50). The roadways chosen are mostly in District 3, except for the I-80 section and part of the I-505 section, which are both in District 4. GPR data was collected on 681 lane-miles of the pilot network and analyzed for 305 lane-miles. Traffic data was obtained from Caltrans. Climate regions were determined from a recent map developed by Caltrans and the University of California Pavement Research Center (UCPRC).

The UCPRC collected coring data for some of the locations on the pilot network. Some of the cores were provided to Infrasense, Inc., for GPR calibration and some were retained by the UCPRC for checking the accuracy of the layer thicknesses and types that Infrasense determined from the GPR data. The UCPRC also collected available as-built information and maintenance records, and the most recent Pavement Condition Survey (PCS) data from Caltrans.

The UCPRC then used the data collected to develop fixed segmentation for the pilot network, resulting in 236 segments for the 305 lane-miles analyzed, with an average segment length of 1.27 miles.

Comparison of the cores retained by the UCPRC with the layer types and thicknesses identified by the GPR showed that the GPR data was reliable, especially for the top two layers of the pavement.

Extrapolation of the costs on the pilot network for data collection and analysis and segmentation results in an estimate of approximately $7.0 million of contracted field work consisting of GPR use and coring (including collection and analysis), plus 12.3 person-years of additional analysis work to complete the segmentation for the entire Caltrans 49,000 lane-mile network.

If Caltrans moves ahead with collection of pavement structure data and fixed segmentation, it will be important to document as-built information in the structural database as future maintenance, rehabilitation, and reconstruction work occurs, in order to keep the database accurate.

Work beyond this pilot study is underway to determine:

* Whether PMS performance data can be used with the fixed segments to develop reasonable performance histories for the segment, and * Whether the performance models developed by the UCPRC from Washington State Department of Transportation (WSDOT) PMS data can be verified with Caltrans PMS performance histories using the fixed network segments and other necessary data developed in this pilot project.

Route 5 near the Florin Road overcrossing (PM 17.2/17.9) in Sacramento County is one of the eight quiet pavement test sections where traffic noise measurements are being conducted by the Caltrans Division of Environmental Analysis Team. This section is a rubberized asphalt concrete open graded (RAC-O) overlay of PCC built in summer 2004.

According to a slide in a PowerPoint presentation prepared by Caltrans Environmental (Figure 1), noise measurements were conducted on the section by Caltrans Environmental between approximately Station 55+40 and Station 60+80 on the southbound lanes and between Station 54+40 and Station 59+60 on the northbound lanes. According to the presentation sent to the Pavement Research Center (PRC) by Caltrans Environmental (Figure 1), both the northbound and southbound directions were divided into three segments of roughly equal lengths (exact stationing of measurements cannot be read from the presentation) and noise levels were obtained for each segment. The total distance over which noise measurements were made for each direction, as approximately read from the presentation, are shown in Figure 2 against the total length of the project. Measurements were repeated three times for each segment to account for measurement errors. According to the presentation, the segments are separated by gaps.

According to the noise levels reported by Caltrans Environmental, noise performance differences exist within the southbound segments as well as between the northbound and southbound directions, though the mix designs of all the segments were the same. Caltrans Environmental reported the following results:

* On the northbound direction, the variation among segments was as small as the difference between run-to-to run. * On the southbound direction, run-to-run differences for each sample segment were smaller than the differences between the segments, indicating that differences were related to variation in the pavement condition of each segment rather than measurement techniques. * Over the project, as much as 3.5-dB variation in noise levels was measured for averages of six different pavement sections. Noise performance differences were significant at lower frequencies (1250 Hz and below). * The overall noise level of the northbound pavement is on average higher than southbound.

PRC evaluation of the results presented in the Caltrans Environmental presentation (Figures 3 and 4) indicate that the maximum difference within the southbound direction is about 3.5 dB, and the difference between the average north and southbound directions is less than 1.5 dB. Verbal communication with Caltrans Environmental indicated that all sound intensity measurements were taken in the outside lane.

On January 26, 2005, a team from the PRC performed a field survey of the project with the following objectives:

* Investigate visual differences in surface condition between northbound and southbound directions * Investigate visual differences in surface condition of different segments of southbound direction where the noise measurements were taken, * Locate any distresses on both directions

It was raining during the visit, which enabled the water handling ability of the pavement to be observed.

This technical memorandum summarizes the analysis performed in evaluating Long-Life Pavement Rehabilitation Strategies (LLPRS) cost. This study is part of the effort to develop an Integrated Pavement Strategy Decision Support System to allow engineers to analyze efficient allocation of financial resources when planning pavement projects. This memorandum is based on data collected as of May 2005. Costs for the I-710 project presented herein are still being accumulated and data and analysis may not be complete.

For this study, cost performances were analyzed for a long-life pavement project on Interstate 710 in Long Beach (EA 07-1384U4) from Route 1 to the Route 405 and 710 separation. Data for this analysis was gathered through the kind cooperation of Caltrans in District 7.

A 4.4-km stretch (total of 26.3 lane-km) of the Interstate 710 was rehabilitated by resurfacing of the existing PCC pavement structure with long-life AC over eight 55-hour weekend closures. The contract was awarded to Excel Paving Company at about $16,743,676.50. Construction began at the end of February 2001 and was completed at the end of 2004.

This technical memorandum summarizes the analysis performed in evaluating the costs associated with Long-Life Pavement Rehabilitation Strategies (LLPRS). This study is part of the effort to develop an Integrated Pavement Strategy Decision Support System to allow engineers to analyze efficient allocation of financial resources when planning pavement projects. For this study, cost performances were analyzed for a long-life pavement project on Interstate 15 in Devore (EA 08-0A4224) between the junctions of Interstate 10 and Interstate 210. This Long Life rehabilitation project involved a 16-km stretch (26.3 lane-km) of Interstate 15. The project involved reconstruction of outer truck lane. The contract was awarded to Coffman Specialties, Inc. at $13,235,000. Construction was begun in July 2004 and was completed in January 2005.