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DCMF Overview



The Development of Crash Modification Factors (DCMF)


The Development of Crash Modification Factors (DCMF) is the next generation of the Evaluation of Low Cost Safety Improvement Pooled Fund Study (ELCSI–PFS). The ELCSI–PFS was established by the Federal Highway Administration (FHWA) in 2004 to develop reliable estimates of the safety effectiveness of low-cost safety improvement strategies. The initial study included four phases, had 23 State participants, and evaluated 20 safety countermeasures in 5 years. Subsequently, three phases were added to the study (for a total of seven studies), and six additional States became participating members. Although its original contract mechanism has now expired, the ELCSI–PFS will continue research under the DCMF umbrella.

Duration: The DCMF is a comprehensive, long-term safety research effort. It started in November 2012 and will end in December 2017.

Goal: The goal of this effort is to develop crash modification factors (CMFs) that meet the criteria for inclusion in the Highway Safety Manual (HSM), and to promote installation of promising safety improvements (low, medium, and high cost) as standard practice and to facilitate developing practical guides for implementation. This study will also address methodological issues with the development, application, and assessment of the quality of CMFs.

Objective: The DCMF study will conduct evaluations of safety improvements through the analysis of crash, road geometry, traffic, pavement, environmental, and other related data to estimate the countermeasures’ effectiveness in reducing the frequency and severity of crashes. For each evaluated countermeasure, the study determines and documents a CMF, benefit/cost ratio, and lessons learned from the States’ experiences.

Safety Improvement Selection: The direction of the effort is set largely by a Technical Advisory Committee (TAC) comprised of representatives from each participating pooled fund State. The TAC members meet annually to cast ballots identifying safety improvements of interest for future phases, receive progress updates for ongoing phases of the study, learn about other ongoing safety efforts at the State and Federal levels, and exchange information and ideas with their peers. As this next generation of the ELCSI–PFS takes shape, the study goal is to expand the pool to all States, maximizing both the reach of the study and the knowledge base that drives it.

Technical Advisory Committee Meeting: The TAC Annual Meeting agenda is to generate information critical to States’ safety efforts. Some of the information includes:

  • Adding to a strong knowledge base by bringing the States’ experiences and perspective to the discussion.
  • Revealing new safety strategies or issues facing our Nation’s roadways that may not be receiving proper attention.
  • Increasing the accuracy of study results by having States contribute data and enhance study sample size.
  • Engaging the States in a discussion of issues and challenges confronting each State, and learn how these issues are managed.
  • Determining priority safety improvements for evaluations through balloting conducted in the meeting.

Resources: The data for this study will be gathered from States that either have already implemented the selected safety improvements, or will implement the improvements over the course of a few years for the purpose of evaluation by this study. The greater the number of States implementing the improvements, the faster the rate of "after" data collection, which shortens the total time required for each evaluation.

Methodology: The methodology used will typically be an Empirical Bayes evaluation, using before-and-after data to determine the effectiveness of the selected safety improvements in reducing the number and severity of crashes. The implementation of the improvements and the evaluations will be staggered, grouping a small number of the evaluations together, as appropriate. However, the study goal is to improve current methodology.

Research Product: The final result of the DCMF study will be published by FHWA, and also will serve as a resource for the Highway Safety Manual (HSM) and other technical publications.

For more information, contact:

Roya Amjadi, Research Highway Safety Specialist
Federal Highway Administration.
Office of Safety Research and Development
6300 Georgetown Pike, McLean, VA 22101
Phone: 202–493–3383, Fax: 202–493–3374