CMF / CRF Details

CMF ID: 8015

Install shoulder rumble stripe, widen shoulder from 0 to 2 feet, and pavement resurfacing

Description: A combination of three countermeasures, including shoulder rumble stripe, shoulder widening from 0 to 2 feet, and pavement resurfacing

Prior Condition: Roadway without paved shoulder

Category: Shoulder treatments

Study: Development of Crash Modification Factors for Combined Treatments on Rural Two-lane Roads, CH2M Hill, 2015

Star Quality Rating: 3 Stars   [View score details]
Rating Points Total: 75
Crash Modification Factor (CMF)
Value: 0.822
Adjusted Standard Error:
Unadjusted Standard Error: 0.131
Crash Reduction Factor (CRF)
Value: 17.8   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 13.1
Crash Type: All
Crash Severity: K (fatal),A (serious injury)
Roadway Types: Not specified
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: Rural
Traffic Volume: Minimum of 8000 to Maximum of 17223 Annual Average Daily Traffic (AADT)
Average Traffic Volume:
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: 2004 to 2013
State: MO
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (sites): 885 sites before, 885 sites after
Sample Size (site-years): 8850 site-years before, 8850 site-years after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Nov-10-2016
Comments: 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.