CMF Clearinghouse


Summer 2020

The Summer 2020 edition of CMF Update is the 21st edition of the CMF Clearinghouse e-newsletter. To subscribe, please visit To view archived issues, please visit

In this issue:

CMF Clearinghouse Facelift

The CMF Clearinghouse website was recently updated with various visual and usability improvements. The updated website went live on February 14th, 2020. The content of the website remains the same including links to any page, study, or CMFs.

Some of the visual improvements implemented include:

Featured Resource: Roadway Safety Analysis Videos for CMFs

The AASHTO Highway Safety Manual (HSM) describes a method for predicting crashes among road users on various facility types. While the premise of the predictive method is relatively straightforward (i.e., input traffic volume and roadway characteristics in an equation to estimate crashes by type and severity), practitioners must educate themselves regarding the terminology and nuances to properly apply the predictive method.

To answer the various safety analysis questions, FHWA developed a series of brief (10–15 minute) safety data and analysis training videos. The CMF-related videos are now available on the CMF Clearinghouse and were also recently featured in the FHWA's Safety Compass newsletter. The following is an overview of these videos:

Application of CMFs
This video describes the process of applying CMFs to estimate countermeasure effectiveness, assuming the viewer is familiar with selecting appropriate CMFs and estimating the safety performance of the base condition. The video explains how to define the base condition, how to apply CMFs, and how to compute and interpret the confidence interval.

Selecting a Method to Analyze Multiple CMFs
This video is the first of a two-part series on estimating the combined effect of multiple countermeasures. The video explains how to select an appropriate method based on the scenario of interest, the limits of the combined effect, the potential for overlapping effects among countermeasures, and the magnitude of countermeasure effects.

Applying a Method to Analyze Multiple CMFs
This video is the second of a two-part series on estimating the combined effect of multiple countermeasures. The video explains how to apply the additive, multiplicative, dominant effect, and dominant common residuals methods. It also explains how to address scenarios where the CMFs apply to the same or different crash types and severities.

New Feature: Transportation Systems Management and Operations (TSMO) Tags for TSMO related CMFs

FHWA recently published a report on Safety Analysis Needs Assessment for Transportation Systems Management and Operations (TSMO). This report provides a synthesis of safety performance results of  various TSMO strategies along with their current state of practice. It also identifies the CMFs in the CMF Clearinghouse for the various TSMO strategies. These CMFs were recently updated and attached with a TSMO tag to allow for a simplified search using "TSMO" as a search term. A "TSMO" search term has also been added to the common search terms on the CMF Clearinghouse website homepage.

Upcoming CMF Clearinghouse Rating System Changes

The CMF Clearinghouse will be undergoing a transition of its CMF rating system to use the system developed as part of the NCHRP 17-72 project for the 2nd edition of the Highway Safety Manual. The rating system developed as part of the NCHRP 17-72 project is much more detailed and provides scores for different factors including sample size, study design, methodology, and statistical significance. There are multiple levels and associated points for each factor. The total score is calculated by adding the points, with a maximum possible score of 150. The CMF ratings in the CMF Clearinghouse will continue to be presented in the form of a 5-star scale (determined based on the number of points a CMF earned using the rating system developed as part of NCHRP 17-72).

The CMF Clearinghouse team hosted a stakeholder call to understand how this proposed rating transition would affect the field of safety practice and research in May 2020. The next steps in this process are to develop outreach materials describing what's going to change (this would include flyers and videos on what's changing and why), revising the CMF Clearinghouse website display (to accommodate the expanded rating criteria), revising the CMF Clearinghouse user guide, and conducting webinars (to inform practitioners about the effect on searching and selecting CMFs). While the exact launch date for this transition is still to be determined, the CMF Clearinghouse is actively working behind the scenes to ensure a smooth transition for all users.

We expect to send the advance outreach materials to the CMF Clearinghouse users soon informing you of these changes in detail.

Featured CMFs

Conversion of Intersection into High-Speed Roundabout
Crash Modification Factor (CMF) Value: 0.59 (for all crashes at 3- and 4-legged intersections)
Star Quality Rating: Description: 4 Stars

Convert Intersection to Restricted Crossing U-Turn (RCUT) Intersection
Crash Modification Factor (CMF) Value: 0.69 (for all intersection crashes)
Star Quality Rating: Description: 3 Stars

Install High Friction Surface Treatment (HFST)
Crash Modification Factor (CMF) Value: 0.43 (for all crashes)
Star Quality Rating: Description: 5 Stars

Install In-Lane Curve Warning Pavement Markings
Crash Modification Factor (CMF) Value: 0.652 (for all crashes on rural 2-lane undivided roads)
Star Quality Rating: Description: 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 Karen Scurry 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 upload your own file. 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.