CMF / CRF Details
Install dynamic speed feedback sign
Countermeasure ID: 6888
Description: System consisting of a speed measuring device and a message sign that displays feedback to those drivers who exceed a predetermined threshold. It may be the actual speed, a message such as SLOW DOWN, or activation of a warning device, such as beacons or a curve warning sign
Prior Condition: High-crash curve sites with identified speeding problem
Category: Advanced technology and ITS
Study: Evaluation of Dynamic Speed Feedback Signs on Curves: A National Demonstration Project, Hallmark et al., 2015
| Crash Modification Factor (CMF) |
|---|
| Value: | 0.95 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.02 |
| Crash Reduction Factor (CRF) |
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| Value: | 5 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 2 |
| Applicability |
|---|
| Crash Type: | Single vehicle |
| 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: | Undivided |
| Minimum Speed Limit: | 50 |
| Maximum Speed Limit: | 65 |
| Speed Unit: | mph |
| Speed Limit Comment: | |
| Area Type: | Rural |
| Traffic Volume: | Minimum of 400 to Maximum of 8400 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: | 2005 to 2013 |
| Municipality: | |
| State: | AZ,FL,IA,OH,OR,TX,WA |
| Country: | USA |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 73 crashes before, 23 crashes after |
| Sample Size (sites): | 20 sites before, 20 sites after |
| Other Details |
|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Nov 01, 2015 |
| Comments: | This CMF applies to two-lane rural horizontal curves for crashes in the direction of the DSFS system. |
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