CMF / CRF Details
CMF ID: 8978
Install oversized chevron signs
Description: Curve warning treatment with oversized chevron signs
Prior Condition: smaller 12x18in or 24x30in signs
Category: Signs
Study: Safety Evaluation of Two Curve Warning Treatments: In-Lane Curve Warning Pavement Markings and Oversized Chevron Signs, Lyon et al., 2017
Star Quality Rating: | [View score details] |
Rating Points Total: | 105 |
Crash Modification Factor (CMF) | |
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Value: | 0.852 |
Adjusted Standard Error: | |
Unadjusted Standard Error: | 0.189 |
Crash Reduction Factor (CRF) | |
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Value: | 14.8 (This value indicates a decrease in crashes) |
Adjusted Standard Error: | |
Unadjusted Standard Error: | 18.9 |
Applicability | |
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Crash Type: | All |
Crash Severity: | K (fatal),A (serious injury),B (minor injury),C (possible injury) |
Roadway Types: | Not specified |
Street Type: | |
Minimum Number of Lanes: | |
Maximum Number of Lanes: | |
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: | Not specified |
Traffic Volume: | Minimum of 173 to Maximum of 27235 Annual Average Daily Traffic (AADT) |
Average Traffic Volume: | |
Time of Day: | Not specified |
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: | |
Municipality: | |
State: | IA,KS,MO |
Country: | USA |
Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
Sample Size (crashes): | 259 crashes before, 109 crashes after |
Sample Size (sites): | 91 sites before, 91 sites after |
Sample Size (miles): | 19.57 miles before, 19.57 miles after |
Sample Size (miles): | 223.25 mile-years before, 139.36 mile-years after |
Other Details | |
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Included in Highway Safety Manual? | No |
Date Added to Clearinghouse: | Nov 17, 2017 |
Comments: | Small sample size, use with caution |