CMF / CRF Details

CMF ID: 8428

Improve angle of channelized right turn lane

Description: Changes made to the study approaches include: sharpening the flat approach angle typical in traditional designs, reducing the radius, adjusting the stop bar position, and modifying the corner island to increase the line of sight of approaching through traffic.

Prior Condition: Varied depending on intersection

Category: Intersection geometry

Study: Safety Impacts of a Modified Right Turn Lane Design at Intersections, Schattler and Hanson, 2016

Star Quality Rating: 4 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.558
Adjusted Standard Error:
Unadjusted Standard Error: 0.114
Crash Reduction Factor (CRF)
Value: 44.2   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 11.4
Crash Type: All
Crash Severity: All
Roadway Types: Not specified
Number of Lanes: 1 to 3
Road Division Type:
Speed Limit:
Area Type: Not specified
Traffic Volume:
Average Traffic Volume:
Time of Day: All
If countermeasure is intersection-based
Intersection Type: Roadway/roadway (not interchange related)
Intersection Geometry: Not specified
Traffic Control: Other
Major Road Traffic Volume:
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used: 2003 to 2016
Municipality: Peoria
State: IL
Country: USA
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 274 crashes before, 161 crashes after
Sample Size (sites): 7 sites before, 7 sites after
Sample Size (site-years): 21 site-years before, 21 site-years after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Jan-17-2017
Comments: Total intersection AADT ranged from 3300 to 41300. Group of intersections analyzed included both signalized and stop-controlled intersections.


The information contained in the Crash Modification Factors (CMF) Clearinghouse is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in the CMF Clearinghouse. The information contained in the CMF Clearinghouse does not constitute a standard, specification, or regulation, nor is it a substitute for sound engineering judgment.