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Crash Modification Factors in Practice: Quantifying Safety in the Roadway Safety Management Process - Virginia Case Study

Summary from Crash Modification Factors in Practice: Quantifying Safety in the Roadway Safety Management Process

(The Virginia case study begins on Page 7 of the full report, after background information about the use of crash modification factors to quantify roadway safety.)

Publication Year: 2013


In 2007, the Virginia Department of Transportation (VDOT) started a new program, Strategically Targeted Affordable Roadway Solutions (STARS), aimed at critical safety and congestion hot spots throughout the State. The primary goals of the STARS program are to identify roadway improvements on the interstate and primary systems that:

  • Are relatively low-cost.
  • Address existing mobility and safety problem areas.
  • Require minimal preliminary engineering and right-of-way.
  • Can be implemented quickly (24 months or less).

The STARS program allows VDOT to better incorporate operations and safety into the long-term planning process and involves the following four steps.

  1. Study area selection.
  2. Detailed safety and operational analysis.
  3. Prioritization of recommendations.
  4. Programming and implementation.

In this process, the study team identifies potential safety and operational issues in Step 2 along with a list of potential countermeasures. Crash Modification Factors (CMFs) are then applied in Step 3 to help justify and prioritize the suggestions. Specifically, CMFs are used to estimate the safety impacts associated with each countermeasure.


There are several potential benefits associated with the application of CMFs in the safety management process. Specifically, CMFs provide a means to quantify the safety impacts of decisions and help to raise awareness of safety. The application of CMFs also helps to prioritize potential treatments and provides decision-makers with the information needed to identify cost-effective strategies. VDOT indicated that the STARS program has helped to raise awareness of safety issues at both the State and local level, which has led to more safety-focused projects.

The goal of the STARS program is to identify where safety and congestion issues overlap on the State's roadways. As demonstrated in the case study, CMFs are used in the benefit-cost analysis to quantify the safety impact of the suggested countermeasures. The results of the benefit-cost analysis are beneficial in the prioritization of recommendations as well as the programming and implementation stage. VDOT indicated that STARS-based projects have addressed more crashes and typically involve lower impact treatments (less utility and right of way) that can be implemented more quickly than proposals submitted prior to the STARS program.

Using CMFs as part of the benefit-cost analysis is not only beneficial to prioritizing the suggested countermeasures for a particular site, but also helps in the management of a safety program. The STARS program actively utilizes Highway Safety Improvement Program (HSIP) funds for many of the hot spot locations throughout the State. The CMFs used in the benefit-cost analysis are instrumental in the application process for HSIP funding.


Karen Scurry
FHWA Office

Publication Year: 2013

View more information about CMFs on the web at:
Additional practices in the CMFs in Practice Series:

  • Quantifying Safety in the Roadway Safety Audit Process - Michigan Case Study
  • Quantifying Safety in the Development and Analysis of Alternatives - Arizona and Colorado Case Study
  • Using CMFs to Quantify the Safety Performance of Design Decisions and Exceptions - California and Missouri
  • Evaluating Opportunities Using Predicted Crash Frequency with CMF Adjustment - Missouri Case Study

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