Study Details

Study Title: Evaluation of the safety effectiveness of lane departure countermeasures on two-lane undivided roadways using crash modification factors

Authors: Dissanayake and Galgamuwa

Publication Date: 2019

Abstract: This study investigates the safety effectiveness of commonly used lane-departure countermeasures on Kansas two-lane rural undivided road segments; 2-ft paved shoulders, centerline rumble strips, shoulder rumble strips, and shoulder & centerline rumble strips using crash modification factors (CMFs). Cross-sectional and case-control methods that are based on generalized linear regression assuming a negative binomial error structure and logistic regression models were used respectively. CMFs were calculated for all lane-departure and fatal and injury lane-departure crashes for tangent and curved road segments separately. Model validation of cross-sectional models was carried out using the mean of the absolute residuals and mean squared error (MSE). Classification tables were used to validate the models developed for the case-control method. Cross-sectional and case-control methods showed that all the countermeasures considered in this study were effective in reducing all lane-departure and fatal and injury lane-departure crashes except shoulder rumble strips on curved road segments for all lane-departure crashes. Even though similar results were obtained from both methods, CMFs developed using the cross sectional method demonstrated a narrower range than the case-control method, indicating that the results from the cross sectional method can be considered as more accurate and reliable than those from the case-control method.

Study Citation: Galgamuwa, U., and S. Dissanayake. "Evaluation of the safety effectiveness of lane departure countermeasures on two-lane undivided roadways using crash modification factors". Journal of Transportation Safety and Security, Vol. 11, No.4 (2019), pp.337-397.

Related Citations: Dissanayake, S. and U. Galgamuwa. "Estimating Crash Modification Factors for Lane Departure Countermeasures in Kansas." Center for Transportation Research and Education, Iowa State University, Ames, IA. (December 2017).


CMFs Associated With This Study

Category: Roadway

Countermeasure: Install centerline and shoulder rumble strips

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.86 14 3 Stars Run off road All Not specified Rural
0.89 11 3 Stars Run off road All Not specified Rural
0.94 6 3 Stars Run off road K,A,B,C Not specified Rural
0.87 13 3 Stars Run off road K,A,B,C Not specified Rural
0.68 32 3 Stars Run off road All Not specified Rural
0.75 25 3 Stars Run off road All Not specified Rural
0.73 27 3 Stars Run off road K,A,B,C Not specified Rural
0.51 49 3 Stars Run off road K,A,B,C Not specified Rural

Countermeasure: Install centerline rumble strips

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.96 4 3 Stars Run off road All Not specified Rural
0.94 6 3 Stars Run off road All Not specified Rural
0.96 4 3 Stars Run off road K,A,B,C Not specified Rural
0.95 5 3 Stars Run off road K,A,B,C Not specified Rural
0.91 9 3 Stars Run off road All Not specified Rural
0.87 13 3 Stars Run off road All Not specified Rural
0.89 11 3 Stars Run off road K,A,B,C Not specified Rural
0.88 12 3 Stars Run off road K,A,B,C Not specified Rural

Category:Shoulder treatments

Countermeasure: Install shoulder rumble strips

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.94 6 3 Stars Run off road All Not specified Rural
0.95 5 3 Stars Run off road All Not specified Rural
0.95 5 3 Stars Run off road K,A,B,C Not specified Rural
0.94 6 3 Stars Run off road K,A,B,C Not specified Rural
0.85 15 3 Stars Run off road All Not specified Rural
1.25 -25 3 Stars Run off road All Not specified Rural
0.9 10 3 Stars Run off road K,A,B,C Not specified Rural
0.81 19 3 Stars Run off road K,A,B,C Not specified Rural

Countermeasure: Provide 2-ft paved shoulders (both sides)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.88 12 3 Stars Run off road All Not specified Rural
0.89 11 3 Stars Run off road All Not specified Rural
0.94 6 3 Stars Run off road K,A,B,C Not specified Rural
0.93 7 3 Stars Run off road K,A,B,C Not specified Rural
0.82 18 3 Stars Run off road All Not specified Rural
0.66 34 3 Stars Run off road All Not specified Rural
0.84 16 3 Stars Run off road K,A,B,C Not specified Rural
0.79 21 3 Stars Run off road K,A,B,C Not specified Rural