CMF / CRF Details

CMF ID: 10011

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: 85
Crash Modification Factor (CMF)
Value: 0.897
Adjusted Standard Error:
Unadjusted Standard Error: 0.092
Crash Reduction Factor (CRF)
Value: 10.3   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 9.2
Crash Type: All
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
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
State: VA
Country: United States
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 488 crashes before, 114 crashes after
Sample Size (sites): 6 sites before, 6 sites after
Sample Size (site-years): 24 site-years before, 6 site-years after
Sample Size (miles): 12.4 miles before, 12.4 miles after
Sample Size (miles): 49.6 mile-years before, 12.4 mile-years after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Jul-26-2019
Comments: Applies to a corridor with a mix of advisory variable speed limits, lane use control signals, and hard shoulder running along the corridor.