CMF / CRF Details
Implement Active Traffic Management Strategies
Countermeasure ID: 10022
Description: Implement a combination of Advisory Variable Speed Limits and Lane Use Control Signs on a section of interstate.
Prior Condition: Interstate segment with static speed limits and no lane use control signals.
Category: Advanced technology and ITS
Study: Evaluation of the Impact of the I-66 Active Traffic Management System: Phase II, Dutta et al., 2018
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 105 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 1.152 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.09 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | -15.2 (This value indicates an increase in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 9 |
| Applicability | |
|---|---|
| Crash Type: | All |
| Crash Severity: | All |
| Roadway Types: | Principal Arterial Interstate |
| Street Type: | |
| Minimum Number of Lanes: | 6 |
| Maximum Number of Lanes: | 8 |
| Number of Lanes Direction: | |
| Number of Lanes Comment: | |
| Crash Weather: | Not specified |
| Road Division Type: | Divided by Median |
| Minimum Speed Limit: | |
| Maximum Speed Limit: | |
| Speed Unit: | |
| Speed Limit Comment: | |
| Area Type: | Suburban |
| Traffic Volume: | Minimum of 167000 to Maximum of 184000 Annual Average Daily Traffic (AADT) |
| Average Traffic Volume: | 176667 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 | |
|---|---|
| Date Range of Data Used: | 2011 to 2016 |
| Municipality: | |
| State: | VA |
| Country: | United States |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 704 crashes before, 212 crashes after |
| Sample Size (sites): | 3 sites before, 3 sites after |
| Sample Size (site-years): | 12 site-years before, 3 site-years after |
| Sample Size (miles): | 5.8 miles before, 5.8 miles after |
| Sample Size (miles): | 23.2 mile-years before, 5.8 mile-years after |
| Other Details | |
|---|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Jul 26, 2019 |
| Comments: | Applies to a segment with advisory variable speed limits and lane use control signals. |
