CMF / CRF Details

Implement systemic signing and visibility improvements at signalized intersections

Countermeasure ID: 8976

Description: Replace all signal heads. Replace pedestrian signal heads, pushbuttons, and signs. Install backplates with retroreflective borders on all signal heads. Re-stripe stop lines. Re-stripe crosswalks. Install advance warning signs. Install overhead signs (e.g., R10‐12, R3‐5L, R3‐5R in the MUTCD(4)). Install curb ramps.

Prior Condition: Signalized intersection without systemic signing and visibility improvements

Category: Intersection traffic control

Study: Safety Effects of Low-Cost Systemic Safety Improvements at Signalized and Stop-Controlled Intersections, Le et al., 2017

 
Star Quality Rating:3 Stars  [View score details]
Rating Points Total:100
Crash Modification Factor (CMF)
Value:0.958
Adjusted Standard Error:
Unadjusted Standard Error:0.055
Crash Reduction Factor (CRF)
Value:4.2  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:5.5
Applicability
Crash Type:Nighttime
Crash Severity:All
Roadway Types:All
Street Type:
Minimum Number of Lanes:2
Maximum Number of Lanes:4
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:All
Traffic Volume:
Average Traffic Volume:
Time of Day:Night
If countermeasure is intersection-based
Intersection Type:
Intersection Geometry:4-leg
Traffic Control:Signalized
Major Road Traffic Volume:Minimum of 4272 to Maximum of 41100 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:Minimum of 111 to Maximum of 20000 Annual Average Daily Traffic (AADT)
Average Major Road Volume :20447 Annual Average Daily Traffic (AADT)
Average Minor Road Volume :5864 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used:2005 to 2014
Municipality:
State:SC
Country:
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (sites):55 sites before, 55 sites after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Nov 17, 2017
Comments:CMF for 4 mainline lanes and 2 cross street lanes 4-legged intersections. 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.

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