CMF / CRF Details

CMF ID: 10020

Implement Active Traffic Management Strategies with Hard Shoulder Running

Description: Implement a mix of advisory variable speed limits, lane use control signals, and hard shoulder running on a segment of interstate.

Prior Condition:  Static speed limits, no lane use control signals, and no hard shoulder running.

Category: Advanced technology and ITS

Study: Evaluation of the Impact of the I-66 Active Traffic Management System: Phase II, Dutta et al., 2018

Star Quality Rating:3 Stars  [View score details]
Rating Points Total:105
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.071
Crash Reduction Factor (CRF)
Value:30.9  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:7.1
Crash Type:Rear end
Crash Severity:All
Roadway Types:Principal Arterial Interstate
Street Type:
Minimum Number of Lanes:6
Maximum Number of Lanes:8
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:Divided by Median
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:Not specified
Traffic Volume:Minimum of 133000 to Maximum of 184000 Annual Average Daily Traffic (AADT)
Average Traffic Volume:158746 Annual Average Daily Traffic (AADT)
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:2011 to 2016
Country:United States
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):616 crashes before, 111 crashes after
Sample Size (sites):3 sites before, 3 sites after
Sample Size (site-years):12 site-years before, 3 site-years after
Sample Size (miles):7.2 miles before, 7.2 miles after
Sample Size (miles):28.8 mile-years before, 7.2 mile-years after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Jul 26, 2019
Comments:Applies to a segment with advisory variable speed limits, lane use control signals, and hard shoulder running.