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Abstract

Transportation practitioners use crash modification factors/functions (CMFs) to calculate the number of crashes expected once a countermeasure has been implemented. When evaluating design alternatives, CMFs can be used in conjunction with safety performance functions (SPFs) to derive crash predictions. The Federal Highway Administration (FHWA) maintains the CMF Clearinghouse as a repository for CMFs. Contributions are submitted by researchers across the U.S., Canada, and throughout the world. Typically, individual countermeasures are associated with multiple CMFs. Some CMFs only apply to a specific facility or crash types. CMF quality varies, and some only apply to a specific facility and/or crash types, regions, or times. One drawback of the CMF Clearinghouse is that practitioners must devote considerable time and have significant expertise to identify an appropriate CMF. To streamline the process of selecting CMFs, Kentucky Transportation Center (KTC) researchers updated a web-based CMF tool they originally developed in 2020. Kentucky Transportation Cabinet staff and design consultants can use the refreshed tool to select CMFs most appropriate for the state’s highways and conditions. The updated tool contains significant enhancements. In addition to having a more intuitive user interface layout and better aesthetics, the new tool incorporates more than 6,000 additional CMFs that have been added to the CMF Clearinghouse. Researchers also optimized the tool for viewing on mobile devices.

Report Date

6-2026

Report Number

KTC-26-31

Digital Object Identifier

https://doi.org/10.13023/ktc.rr.2026.31

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