scope:

TRB's second Strategic Highway Research Program (SHRP 2) Report S2-L07-RR-2: Design Guide for Addressing Nonrecurrent Congestion catalogs highway design treatments that can be used to reduce nonrecurrent congestion and improve the reliability of urban and rural freeways.

The draft design guide is accompanied by a report titled Identification and Evaluation of the Cost-Effectiveness of Highway Design Features to Reduce Nonrecurrent Congestion.

SHRP 2 Reliability Project L07 also produced an Analysis Tool for Design Treatments to Address Nonrecurrent Congestion: Annotated Graphical User's Guide Version 2. The guide is intended to assist users of the Microsoft-based Excel tool designed to analyze the effects of highway geometric design treatments on nonrecurrent congestion using a reliability framework.

The tool is designed to analyze a generally homogenous segment of a freeway (typically between successive interchanges). The tool allows the user to input data regarding site geometry, traffic demand, incident history, weather, special events, and work zones. Based on these data, the tool calculates base reliability conditions. The user can then analyze the effectiveness of a variety of treatments by providing fairly simple input data regarding the treatment effects and cost parameters. As outputs, the tool predicts cumulative travel time index curves for each hour of the day, from which other reliability variables are computed and displayed. The tool also calculates cost-effectiveness by assigning monetary values.

Subsequent to the analysis tool's release, SHRP 2 Reliability Project L07 produced a Microsoft-based Excel demand generator as a supplement to the analysis tool.