CMF / CRF Details

CMF ID: 10988

Install Slip Lane


Prior Condition: No slip lane

Category: Intersection geometry

Study: Development of Crash Modification Factors for Intersections in Toowoomba city, Al-Marafi et al., 2020

Star Quality Rating: 2 Stars   [View score details]
Rating Points Total: 60
Crash Modification Factor (CMF)
Value: 0.97
Adjusted Standard Error:
Unadjusted Standard Error: 0.05
Crash Reduction Factor (CRF)
Value: 3   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 5
Crash Type: All
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types: All
Street Type:
Minimum Number of Lanes: 2
Maximum Number of Lanes: 5
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather: Not specified
Road Division Type: All
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type: All
Traffic Volume:
Average Traffic Volume:
Time of Day: All
If countermeasure is intersection-based
Intersection Type: Roadway/roadway (not interchange related)
Intersection Geometry: 3-leg,4-leg
Traffic Control: Other
Major Road Traffic Volume: Minimum of 4500 to Maximum of 21784 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume: Minimum of 1600 to Maximum of 14837 Annual Average Daily Traffic (AADT)
Average Major Road Volume : 12546 Annual Average Daily Traffic (AADT)
Average Minor Road Volume : 5769 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used: 2008 to 2015
Municipality: Toowoomba City
Country: Australia
Type of Methodology Used:
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Aug-11-2021
Comments: This CMF is for installing a slip lane on one major road approach. Intersections are a combination of signalized and un-signalized.