CMF / CRF Details

CMF ID: 4172

Changing left turn phasing from protected to flashing yellow arrow (FYA)

Description: CMFs are calculated the intersection level and not the treated approach(es) level.

Prior Condition: All treated approaches had protected left turn

Category: Intersection traffic control

Study: Evaluation of Safety Strategies at Signalized Intersections, Srinivasan, et al., 2011

Image: View the countermeasure image.

Star Quality Rating: 5 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 1.338
Adjusted Standard Error:
Unadjusted Standard Error: 0.097
Crash Reduction Factor (CRF)
Value: -33.8   (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 9.7
Crash Type: All
Crash Severity: All
Roadway Types: Not Specified
Number of Lanes:
Road Division Type:
Speed Limit:
Area Type: Urban
Traffic Volume:
Average Traffic Volume:
Time of Day: Not specified
If countermeasure is intersection-based
Intersection Type: Roadway/roadway (not interchange related)
Intersection Geometry: 4-leg
Traffic Control: Signalized
Major Road Traffic Volume: Minimum of 8260 to Maximum of 43000 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume: Minimum of 600 to Maximum of 13745 Annual Average Daily Traffic (AADT)
Average Major Road Volume : 22575 Annual Average Daily Traffic (AADT)
Average Minor Road Volume : 4285 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used:
State: NC, OR, WA
Country: USA
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (sites): 29 sites before, 29 sites after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Dec-06-2012