CMF / CRF Details

CMF ID: 9141

Install automated section speed enforcement system

Description: Installation of automated speed enforcement system. Determines average speed of vehicle over a long distance.

Prior Condition:  No automatic speed enforcement

Category: Advanced technology and ITS

Study: Safety Impact of Average Speed Control in the UK, Lahrmann et al., 2016

Image: View the countermeasure image.

Star Quality Rating:2 Stars  [View score details]
Rating Points Total:65
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.07
Crash Reduction Factor (CRF)
Value:24  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:7
Crash Type:All
Crash Severity:K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types:Not specified
Street Type:
Minimum Number of Lanes:2
Maximum Number of Lanes:4
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:
Minimum Speed Limit:30
Maximum Speed Limit:60
Speed Unit:mph
Speed Limit Comment:
Area Type:All
Traffic Volume:Minimum of 8000 to Maximum of 38000 Annual Average Daily Traffic (AADT)
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:
Intersection Geometry:
Traffic Control:
Major Road Traffic Volume:
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:
Municipality:Nottingham and Nottinghamshire
Country:United Kingdom
Type of Methodology Used:Before/after using comparison group
Sample Size (crashes):675 crashes before, 590 crashes after
Sample Size (sites):10 sites before, 10 sites after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Jan 17, 2018