Identifying and Quantifying Operational and Safety Performance Measures for Access Management: Micro-Simulation Results (SWUTC/05/167725-1)

This research report summarizes the activities of a research project intended to identify and quantify appropriate operational and safety performance measures that can be use for investigating access management treatments. Specifically, the research had three objectives: 1)assess the state-of-the-practice relative to performance measures that are applicable to access management and identify existing and/or new measures-particularly measures that can capture the safety benefits of access management treatments. 2) perform micro-simulation using the identified measures on two selected case study corridors and on three theoretical corridors to demonstrate the application of the measures, and 3) develop guidance for applying the performance measures for evaluating roadway improvements that include access management treatments (e.g., raised medians, driveway consolidation) and incorporating them into the transportation planning process. The research will be useful to practitioners as it identifies desirable input and output characteristics for individuals searching for a micro-simulation tool to use for assessing the impacts of access management. It also identifies surrogate safety measures related to time-to-collision (ITC), and incorporates them into a micro-simulation model (VISSIM) as a demonstration of how both safety and operational impacts might be investigated in the same software package. Generally, the results appear intuitive-particularly at lower volumes and for the theoretical corridors. The research report also discusses how the safety measures can be incorporated into the traditional transportation planning process. It also cautions that corridor improvements are very case specific and illustrates how micro-simulation, when calibrated appropriately to field conditions, provides a tool to estimate the effects of combined corridor characteristics. Finally, the research report concludes with future research needs that can enhance the state-of-the-practice in this area.