CMF / CRF Details

Implement systemic signing and marking improvements at stop-controlled intersections

Countermeasure ID: 8911

Description: Double‐up (i.e., both right and left side) 36 in. x 36 in. intersection warning signs (W2- 22 series in the MUTCD (4)) on fluorescent yellow sheeting. Add advance street name plaque (W16‐8 in the MUTCD(4)) on fluorescent yellow 24 sheeting accompanying each right‐side intersection warning sign. Double-up (i.e., both right and left side) 48 in. x 48 in. STOP or YIELD signs (R1‐1 and 26 R1‐2 in the MUTCD(4)). Install retroreflective strips on sign posts for the above signs. Place minor road stop bars within 4 to 10 ft of the edge of the nearest through lane along the major road. Install yield bars at all lanes having yield conditions. Add dashed white edge-lines along the major road through the intersection. Remark all existing stop bars, crosswalks, arrows and word messages unless: o The roadway has been resurfaced within one calendar year and new thermoplastic markings have been applied. o Existing markings are uniformly reflective and above ground thickness is 90 mils or greater. o Otherwise directed by a district representative. Mark all turn lanes to include the pattern of lane arrows and text marking “ONLY” based on the turn lane length.

Prior Condition: Stop-controlled intersections without systemic signing and marking 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:0.979
Adjusted Standard Error:
Unadjusted Standard Error:0.063
Crash Reduction Factor (CRF)
Value:2.1  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:6.3
Applicability
Crash Type:Nighttime
Crash Severity:All
Roadway Types:All
Street Type:
Minimum Number of Lanes:2
Maximum Number of Lanes:2
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:3-leg
Traffic Control:Stop-controlled
Major Road Traffic Volume:Minimum of 641 to Maximum of 41731 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:Minimum of 102 to Maximum of 8436 Annual Average Daily Traffic (AADT)
Average Major Road Volume :11042 Annual Average Daily Traffic (AADT)
Average Minor Road Volume :1453 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):116 sites before, 116 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 stop-controlled 3-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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