Development of an Enhanced Transportation-Leveraging Investments in Kansas (T-LINK) Calculator

The purpose of this study was to evaluate and explain the safety and economic benefits of different transportation system enhancement options in the Transportation-Leveraging Investments in Kansas (T-LINK) Calculator. The research team reviewed the literature, the Kansas Department of Transportation (KDOT) records and historical data (in coordination with KDOT) with the goal of identifying models that will enable the user to project the relative benefits of various transportation options. These benefits were expressed in terms of: expected reductions in crashes, injuries, and fatalities; expected crash cost saving; benefit and cost ratios; and economic development benefits. Specifically, this project focused on four common roadway improvements used in the T-LINK Calculator: widening shoulder, installing passing lanes, converting rural two-lane road to four-lane road, and upgrading intersections to interchanges. This report discusses how historical data and Crash Modification Factors (CMFs) were combined to estimate the safety benefits of the studied treatments. The objective was to determine specific CMFs for the State of Kansas and states with similar rural environments, as well as to estimate the number of crashes avoided. Safety and traffic volume data for various research areas were obtained from the State of Kansas and combined with existing models from earlier studies to create state-specific CMFs to more accurately estimate safety benefits. It was determined in this study that CMFs for the four improvements are 0.95, 0.65, 0.4 and 0.22 respectively. Based on these results, 20-year projections were developed projecting the benefits in crash reductions that can be achieved through implementing these safety improvements. Also, benefit-cost ratios were determined for every improvement. Finally, recommendations about how to enhance the T-LINK Calculator were given.