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Iowa State University--Becoming the Best

Development of Crash Modification Factors for Lane Departure Countermeasures


Principal investigators:

Project status


Start date: 08/01/14
End date: 12/31/17


Related publications:



About the research


Lane departure crashes make up a large percentage of rural crashes for states in the midwest. Since agencies have limited resources, they rely on studies that demonstrate the effectiveness of a particular countermeasure in order to make decisions about which countermeasures should be selected. Most agencies prefer countermeasure effectiveness to be stated in terms of crash modification factors (CMFs) since they are easily understood and commonly used by agencies. Developing data driven performance measures for safety is one of the main Midwest Transportation Center (MTC) themes and robust CMFs have not been developed for a number of lane departure countermeasures.

The objective of this research is to develop CMFs for several lane departure countermeasures that have been used in Iowa. The research includes selecting sites where the countermeasures have been installed, identifying control sites, extracting site characteristics, reducing crash data, conducting analyses, and summarizing results. The team developed tech briefs for the following lane departure countermeasures as determined by the technical advisory committee:

·         Safety Edge

·         Chevrons

·         Destination lighting at stop-controlled intersections

·         Stop-sign beacons