Developing CMFs

Many researchers conduct studies in which they develop CMFs. However, it takes planning and intentional study design to produce good quality CMFs. The following resources provide guidance on how to produce the best quality CMFs as well as information on current CMF research needs.

CMF Clearinghouse Flyer: "Better CMFs , safer roadways: Tips for building high-quality CMFs "
This two-page flyer provides a basic overview on how to develop high-quality CMFs, with information on questions such as, "What does a quality CMF study look like?" and "Why is documentation important?"

A Guide to Developing Quality Crash Modification Factors
The purpose of this guide is to provide direction to agencies interested in developing crash modification factors (CMFs). Specifically, this guide discusses the process for selecting an appropriate evaluation methodology and the many issues and data considerations related to various methodologies.

Recommended Protocols for Developing Crash Modification Factors
The CMF Protocols provide guidance for the development and documentation of research studies that develop CMFs. The major goal of these protocols is to describe what pieces of the research study should be documented by the study authors and how various potential biases should be addressed.

Quick Reference on What to Document about the CMF You Have Developed
This 2-page appendix from the above document provides a summary of the items should be documented in a report or article from a study which developed CMFs. It can serve as a quick reference for study authors to make sure that all necessary information has been included in the report. This information is critical for safety practitioners who need to know how this CMF can be applied and the CMF Clearinghouse team who need to know how to rate the CMF.

CMF Needs

  • CMF Most Wanted List
    The research topics in this list represent areas where crash-based safety evaluation research is needed.
  • CMF Needs Assessment
    This report summarizes the proceedings of a workshop in 2014 that brought together CMF stakeholders to identify CMF research needs.
  • Submit a CMF Research Need
    If you see a lack of CMFs for a particular topic, submit your idea for a future research need.


  • Developing Quality CMFs
    Coming soon via NHI

Submit a CMF
If you have conducted a study that produced CMFs, submit your report to be reviewed and included on the Clearinghouse.