UDOT Highway Safety Manual (HSM) Application Technical Assistance

KAI provides on-going technical assistance to UDOT for implementing the HSM within on-going projects and studies to help inform project decisions. Work has also included reviewing the quality of crash modification factors used to help evaluate the safety performance of design exceptions. Specific analysis tasks have included:

  • Evaluating the anticipated safety performance of alternative cross-sections for SR 37. The existing rural highway is anticipated to experience notable amount of growth in the near future due to surrounding development. KAI conducted HSM analysis for three alternative conditions to identify the potential safety performance tradeoffs and opportunities to improve the alternatives to arrive at a configuration able to accommodate the anticipated growth while reducing the likelihood of crashes.
  • Conducting safety performance and cost effectiveness evaluation of alternative shoulder widths for SR 111, a two-lane rural highway. KAI considered the relative effectiveness of varying shoulder widths over the course of the study section. UDOT was fiscally constrained and could not increase shoulder width to the standard width for the full length of the study section. Therefore, we considered alternatives that included shoulder widths less than standard, greater than existing and could be implemented the full length of the study corridor.
  • Assessing the potential tradeoffs of narrowing shoulders to create space for express lanes on I-15. KAI used the research results from NCHRP 17-45: Final Report Safety Prediction Methodology and Analysis Tool for Freeways and Interchanges to assess the relative expected difference in crash frequency and severity if the width of the shoulders on I-15 were reduced to accommodate additional travel lanes.

For each of the analyses above and other similar assessments, KAI prepared a summary of analysis approach and results and also provided support to UDOT in discussing the results and identifying actions or decisions informed by the results. UDOT considered the first year of this technical assistance such a success, that they initiated continuing the on-going technical assistance support.