FHWA project synthesizes CMF service life and crash severity costs data, develops user guide to inform safety improvement decision making

When commuting to work or running errands, a typical driver spends little time thinking about the decisions that go into the construction and maintenance of the roadways on which they travel. However, safety decisions are made every day, and it is imperative for transportation safety researchers and practitioners to have as much information as possible to help inform these decisions and to improve roadway infrastructure safety in a cost effective manner.

A recent FHWA-sponsored project synthesized multitudes of data for this exact purpose. Synthesis of Countermeasure Service Life and Crash Severity Costs User Guide is now available on the CMF Clearinghouse website, www.cmfclearinghouse.org.

“It is important for researchers and practitioners to have as much information as possible when selecting which countermeasures to use to improve roadway and infrastructure safety,” said Sarah Smith, HSRC engineering research associate. “Crash based cost/benefit analyses are a great tool for states to use to determine which countermeasures would be most cost effective for reducing the number and severity of crashes.”

As part of the HSRC synthesis project, researchers searched various sources for available resources, identified the relevant information and organized it in two databases: one for countermeasure service life and the other for crash severity costs. Most states compile their own, separate information on service lives of countermeasures and crash severity costs to use for economic appraisals, and some of this documentation is publicly available on state departments of transportation safety websites or published in FHWA Highway Safety Improvement Program (HSIP) manuals. However, all of this available information has never before been compiled and accessible in one place.

More on CMFs, service life and crash severity costs

Crash modification factors (CMFs) can help highway safety and traffic engineers, highway designers, and transportation planners, identify the most effective countermeasures – or changes to a roadway – that can be made to improve safety. Transportation professionals use CMFs to compute the expected number of crashes at a specific location after making a change (like adding a signal to an intersection, or adding a paved shoulder on the side of a road), often comparing that number to the current number of crashes at the site.

When selecting which countermeasure to use in a given area, transportation professionals may also consider its service life – the amount of time the countermeasure is expect to last before needing replacement – and crash severity costs – the economic impact of a crash based on its injury severity. Both of these pieces of information assist in the economic side of the decision making process; service life and crash severity costs allow the roadway designer to conduct a cost/benefit analysis for implementing a particular improvement over a given period of time.