CMF / CRF Details
CMF ID: 7009
Improve pavement friction (Chip Seal)
Description:
Chip seal treatment to improve pavement friction
Prior Condition: No Prior Condition(s)
Category: Roadway
Crash Modification Factor (CMF) |
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Value: | 0.883 |
Adjusted Standard Error: | |
Unadjusted Standard Error: | 0.028 |
Crash Reduction Factor (CRF) |
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Value: | |
Adjusted Standard Error: | |
Unadjusted Standard Error: | |
Applicability |
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Crash Type: | Run off road |
Crash Severity: | All |
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: | All |
Minimum Speed Limit: | |
Maximum Speed Limit: | |
Speed Unit: | |
Speed Limit Comment: | |
Area Type: | All |
Traffic Volume: | Minimum of 170 to Maximum of 24792 Annual Average Daily Traffic (AADT) |
Average Traffic Volume: | 2751 Annual Average Daily Traffic (AADT) |
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 |
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Date Range of Data Used: | 2000 to 2011 |
Municipality: | |
State: | CA,MN,NC,PA |
Country: | USA |
Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
Sample Size (miles): | 2448 miles before, 2448 miles after |
Other Details |
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Included in Highway Safety Manual? | No |
Date Added to Clearinghouse: | Nov 01, 2015 |
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. |