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This study evaluated existing traffic signal optimization programs including Synchro,TRANSYT-7F, and genetic algorithm optimization using real-world data collected in Virginia. As a first step, a microscopic simulation model, VISSIM, was extensively calibrated and validated using field data. Multiple simulation runs were then made for signal timing plans such that drivers' behavior, day-to-day traffic variation, etc. were considered in the evaluation. Finally, long-term demand growth or changes were statistically modeled and evaluated, again using multiple simulation runs. Five timing plans were evaluated using the simulation test bed. The timing plans under evaluation included (1) the former timing plan of the Virginia Department of Transportation(VDOT), (2) VDOT's current timing plan, (3) the genetic algorithm optimized timing plan, (4)the Synchro optimized timing plan, and (5) the TRANSYT-7F optimized timing plan. The simulation study results indicated that the current practice of VDOT's current signal optimization procedure significantly improved upon its former one by reducing travel times by 17% and total system delay by 36%. The three "optimized" timing plans did not provide significant improvements. Evaluation of the Lee-Jackson Memorial Highway network showed that the current VDOT signal optimization procedure significantly improved the performance of network operations. Thus, the study recommended that VDOT continue using its procedure for developing new timing plans but that it evaluate its signal timing plan regularly so that it does not become outdated.

The purpose of this research was to determine if data collected from an advanced arterial signal control system could be used to generate information that would be useful for transportation engineering analysis other than signal optimization and control. This research also looked at some of the technical challenges and limitations to using data collected by an arterial signal control system and presents an analysis of the validity of the data. The premise investigated is that data from signal control system surveillance equipment can be used to calculate daily volume counts for a roadway segment. This premise was tested by screening and aggregating data from signal system data collection equipment and comparing it with data from traffic monitoring equipment located in close proximity to the intersections being analyzed.

Prefabricated vertical drains (PVD), also known as wick drains, are commonly used to accelerate the consolidation of fine-grained soils in order to reduce future settlements and increase shear strength. Various drain designs are currently on the market, with significant variations in price. This variability of designs makes the performance highly product specific. Tests were carried out to assess the behavior of several wick drains in Virginia soils. Drains were subjected to crimping, lateral pressure, and consolidation, with the resulting impact on the flow rate. All tests were performed in the laboratory to ensure controlled boundary and initial conditions. Significant differences in the performance of wick drains were evaluated. The performance was quantified based on the percentage reduction in flow capacity during flow in a crimped position, percentage reduction in flow capacity under lateral stress, and percentage reduction in the consolidation time. Test results identified the Ameridrain AD607 and Mebra-Drain MD-88 as themost effective drains among those studied.

Traffic signal optimization is recognized as one of the most cost-effective ways to improve urban mobility; however the extent of the benefits realized could significantly depend on how often traffic signal re-optimization occurs. Using a case study from the Northern Virginia Smart Traffic Signal System (NVSTSS), this project sought to determine how often traffic signals need to be re-optimized to provide the greatest benefits. This project developed a new traffic signal timing plan evaluation and optimization program by combining the Integrated SYNCHRO and Platoon Dispersion (ISAPD) model and the OptQuest optimization program. Based on 2001 (base scenario) and 2004 traffic data, five scenarios of re-optimization time intervals (i.e., 2 weeks, 4 weeks, 8 weeks, 16 weeks, and 1 year) were investigated. Study results indicate that (1) determining time intervals for re-optimization in the NVSTSS is feasible; (2) among the various re-optimization time intervals investigated for the Route 50 case study network, the time interval of 1 year was the best for both midday and the PM peak; and (3) the annual net savings from implementing this 1-year re-optimization time interval could be as high as $107,340 and $254,436, respectively, given the assumptions used in the study. The report recommends (1) the annual re-optimization of the Route 50 corridor traffic signal system; (2) the NVSTSS implementation of the combined ISAPS and OptQuest program for measuring "regrets" of not maintaining the optimal timing plan; (3) the adoption by VDOT traffic engineers of the methodology developed in this study, which is based on the combined ISAPD and OptQuest program, for making decisions regarding traffic signal re-optimization; and (4) a future study to investigate the impact of traffic volume growth rates and changes in turning movements as a means of assisting with determinations about traffic signal timing plan re-optimization.