CMF Clearinghouse


CMF Clearinghouse Update: Spring 2024

In this issue:

  • RECAP: 2023 CMF Clearinghouse Annual Webinar
  • Recent Updates: CMF Most Wanted List
  • Recent Updates: Improved Filter Functionality
  • New Tool: SPF-R Tool
  • Reminder: State CMF List
  • Featured CMFs
  • Submit a Study

The Spring 2024 edition of CMF Update is the 28th edition of the CMF Clearinghouse e-newsletter. To subscribe, please visit To view archived issues, please visit To view the CMF Clearinghouse brochure, please visit

RECAP: 2023 CMF Clearinghouse Annual Webinar

During the December 2023 webinar, CMFs In Real Life: Issues, Tools, and Applications, Sarah Weissman Pascual and Matt Hinshaw, Federal Highway Administration (FHWA), provided an overview of the CMF Clearinghouse. Vikash Gayah, Pennsylvania State University (PennState), presented on recent efforts to update CMFs for High-Friction Surface Treatment (HFST) and High-Tension Cable Median Barriers (HTCMB) in Pennsylvania. Chris Cunningham, North Carolina State University Institute for Transportation Research and Education, presented on a recent effort to develop CMFs for Continuous Flow Intersections (CFIs). Raghavan Srinivasan, University of North Carolina Highway Safety Research Center, provided an overview of the various current and recently completed CMF-related NCHRP projects.

Taha Saleem, University of North Carolina Highway Safety Research Center, presented an overview of resources available for your assistance and demonstrated how to make use of the features of the CMF Clearinghouse to sort through hundreds of countermeasures and CMFs to find the most appropriate CMF for your situation.

Click HERE to watch the recorded webinar and download the presentations.

CMF Most Wanted List

The CMF Most Wanted List represents focus areas or specific countermeasures for which the CMF Clearinghouse does not have CMF information. Essentially, the question posed was, "what are people searching for but not finding?" This list was updated based on an analysis of user searches made from July 2019 to September 2023. The items listed in the CMF "Most Wanted" list represent focus areas (grouped by themes) where crash-based safety evaluation research is needed. The safety research community can use this list to prioritize research needs statements, particularly those which deal with evaluations of specific countermeasures.

Recent Updates: Improved Filter Functionality

On the search results page, users can filter results using the left-hand tool to remove CMFs irrelevant for their needs. In response to user feedback, a new filter parameter – Publication Year – was added to support users narrow results based on the publication year of the CMF research. The following filters are currently provided: area type, country, crash severity, crash time of day, crash type, crash weather, intersection geometry, intersection type, publication year, roadway type, star quality rating, traffic control and whether the CMF appears in the Highway Safety Manual.

New Tool: SPF-R Tool

The updated SPF-R tool developed by the Kentucky Transportation Center was recently made available on the CMF Clearinghouse website on the How to Develop and Use SPFs page. This tool uses the free and open-source statistical computing and graphics environment “R”. Utilizing methods outlined by the HSM, code was created in R to automate SPF development to improve regression models. SPF-R provides immediate feedback in SPF development, including goodness-of-fit measures and depictions of the model.

Recognizing that running code locally may be a barrier for some, this new version runs on a server. A new web interface was developed so SPFs could be developed through a user’s web browser simply by uploading a CSV file with certain predefined parameters. Users of this new tool will have fewer technical challenges getting SPF-R working as the mechanics are all handled online. SPF-R online is still free and open-source, but in this current form it is more accessible than ever before.

Reminder: State CMF List

Did you know that the CMF Clearinghouse website also provides a comprehensive list of State Selected CMFs? States compiled these lists to ensure consistency in CMF use across their state. Listed CMFs were identified from the CMF Clearinghouse and other resources relevant for State analysis.

If your State has developed state-selected CMF lists or you have an updated list, please contact Sarah Weissman Pascual at to have them featured on the CMF Clearinghouse.

Featured CMFs 

Crash Modification Factor (CMF) Value: 0.664 (for total reported wildlife-vehicle crashes from carcass removals)

Star Quality Rating: 3 Stars


Crash Modification Factor (CMF) Value: 0.85 (for all left turn crashes and FYA intersections with dual left-turn lanes)

Star Quality Rating: 4 Stars

Submit a Study 

The CMF Clearinghouse welcomes CMF study submissions to be included in its searchable database. If you wish to submit your CMF study, please email Sarah Weissman Pascual at Be sure to search the Clearinghouse before submitting a new CMF as we may already have it listed. You may either send a link to a resource already existing on the web (preferred) or include it as an attachment in the email. Submissions might include published research studies that are not presented in the Clearinghouse, or state-specific CMFs that were developed as part of the Highway Safety Improvement Program. Please note that the Clearinghouse only includes CMFs that are derived and presented in the studies by the authors.

Funded by the U.S. Department of Transportation
Federal Highway Administration and maintained by the
University of North Carolina Highway Safety Research Center.

For more information, contact Sarah Weissman Pascual at