INDOT units responsible for planning and pre-engineering analysis consider safety implications of studied alternative roadway and road network solutions to the extent allowed by the available tools. This project is meant to enhance the available tools of predicting crash frequencies in future road networks to improve the quality of safety consideration in intermediate and long-term road planning.

Safety Performance Functions are widely used to estimate and predict road safety at intersections and on segments. Evaluation of the performance of the functions developed for regions other than Indiana indicated that only full recalibration, which is in fact equivalent to developing own models, gives a chance of obtaining a useful prediction tool for Indiana conditions. Such Safety Performance Functions have been developed for Indiana and implemented in TransCAD by the means of two tools: Indiana Input to Safety In Planning tool (INSIP) and Safety In Planning tool (SIP). INSIP allows reformatting the data available in Indiana to the format that is required by the developed SPFs. INSIP creates intersection data tables that allow predicting crashes separately for segments and separately for intersections. In addition, the INSIP reformats the crash data to the format acceptable by the TransCAD and assigns crashes to segments and intersections. The second component – SIP calculates crashes for segments and intersections in studied road networks. It includes a convenient SPF editor that allows modifying the existing SPFs and entering new ones. Also, the INSIP facilitates calibration of the SPFs based on the user-defined partitioning of the road network. A user manual has been developed to assist analysts use the INSIP and SIP.

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safety prediction, transportation planning, corridor study, add-on tools, SPR-2875

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Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, IN

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