User-Friendly Traffic Incident Management (TIM) Program Benefit-Cost Estimation Tool

Conclusions

Traffic Incident Management (TIM) programs have been proven effective in mitigating the impact of traffic incidents on roadway safety and mobility performance by supporting quick incident response and clearance. Since some TIM programs can be costly to taxpayers, it is critical to estimate the return on investments of different TIM strategies. Benefit-Cost estimation studies have been conducted for numerous programs, the majority of which are related to SSPs. A wide range of estimation methodologies, however, have been used in these studies, and consequently these B/C ratio estimation results vary widely and are not comparable.

Building on previous efforts of the preliminary SSP-BC tool developed by the University of Maryland,⁽¹²⁾ this study expands the standardized methodology that can be universally and equitably employed in such B/C ratio estimation for different TIM programs. Such a standardized approach is essential to creating consistency and, therefore, greater confidence in the validity of the evaluation results. The methodology was then incorporated into a user-friendly Web-based TIM tool to facilitate cost-effective TIM evaluation by State DOTs. A New York synthetic case study compares the effectiveness of implementing three selected TIM strategies: Safety Service Patrol, Driver Removal Laws, and Dispatch Colocation. The case study example illustrates the B/C ratio estimation methodology and the effectiveness of the developed TIM-BC tool.

While the new TIM-BC tool offers the possibility of evaluating a wider range of TIM programs, there are areas for future studies. For example, evaluation results of different TIM strategies are not additive because benefits and costs of different TIM strategies may not be independent. Future studies should consider potential interactions between different TIM strategies. Moreover, evaluation of other TIM strategies could be added to the TIM-BC tool. Further, finer details of various TIM programs, such as different SSP capacities (e.g., size of vehicles SSPs can move) can be potentially considered to improve the accuracy of the evaluation results. Last, since some key parameters used in the methodology were assumed based on interviews with the project advisory committee, it is necessary to collect more data (traditional and nontraditional) to determine values of these parameters. For example, it is critical to produce better linkages between the various TIM strategies and actual reductions in incident durations.