CMF / CRF Details

CMF ID: 9777

Install adaptive traffic signal control

Description: ATSC is a traffic management strategy in which traffic signal timings change, or adapt, based on observed traffic demand. These systems utilize increased detection to continually collect data on observed demand, and signal timings are then re-optimized based on current data.

Prior Condition: Traditional traffic signal

Category: Intersection traffic control

Study: Estimating Safety Effects of Adaptive Signal Control Technology using the Empirical Bayes Method, Khattak et al., 2018

 
Star Quality Rating: 3 Stars   [View score details]
Rating Points Total: 85
Crash Modification Factor (CMF)
Value: 0.6
Adjusted Standard Error:
Unadjusted Standard Error: 0.21
Crash Reduction Factor (CRF)
Value: 40   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 21
Applicability
Crash Type: Multiple vehicle
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types: Not specified
Number of Lanes:
Road Division Type:
Speed Limit:
Area Type: Urban and suburban
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
Traffic Control: Signalized
Major Road Traffic Volume:
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:
Municipality: Pittsburgh
State: PA
Country: United States
Type of Methodology Used: 2
Sample Size (sites): 3 sites before, 3 sites after
Sample Size (site-years): 6 site-years before, 15 site-years after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Oct-27-2018
Comments: Applies to crashes within 350 feet of an intersection. SURTRAC adaptive signal control system installed The number of crashes in the after period were not reported in this study, however, they have been recorded as 300 to give 10 points as a beneift of doubt for one or more of the following: (1) number of miles/sites in the reference/treatment group, (2) number of crashes in the references/treatment group, (3) reporting AADTs for the aggregate dataset but not for the disaggragate dataset used for CMF development.