CMF / CRF Details

CMF ID: 10016

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: 4 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.753
Adjusted Standard Error:
Unadjusted Standard Error: 0.065
Crash Reduction Factor (CRF)
Value: 24.7   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 6.5
Crash Type: All
Crash Severity: All
Roadway Types: Principal Arterial Interstate
Number of Lanes: 6-8
Road Division Type: Divided by Median
Speed Limit:
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
State: VA
Country: United States
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 816 crashes before, 161 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 a advisory variable speed limits, lane use control signals, and hard shoulder running.