CMF / CRF Details
Increase density of access points
Countermeasure ID: 10121
Description: Safety effects on of spacing of access points (intersections and driveways) along a roadway segment
Prior Condition: Access spacing greater than 1,320 ft
Category: Access management
Study: Examining Safety on Two-Lane and Multilane Highways in Consideration of Access Spacing, Hamzeie et al., 2019
| Crash Modification Factor (CMF) |
|---|
| Value: | 3.473 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.323 |
| Crash Reduction Factor (CRF) |
|---|
| Value: | -247.3 (This value indicates an increase in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 32.3 |
| Applicability |
|---|
| Crash Type: | Other |
| Crash Severity: | All |
| Roadway Types: | Not specified |
| Street Type: | |
| Minimum Number of Lanes: | 3 |
| Maximum Number of Lanes: | |
| Number of Lanes Direction: | Both Directions |
| Number of Lanes Comment: | Multi Lane |
| Crash Weather: | Not specified |
| Road Division Type: | |
| Minimum Speed Limit: | 20 |
| Maximum Speed Limit: | 65 |
| Speed Unit: | mph |
| Speed Limit Comment: | |
| Area Type: | Not specified |
| Traffic Volume: | Minimum of 1060 to Maximum of 41600 Annual Average Daily Traffic (AADT) |
| Average Traffic Volume: | 10411 Annual Average Daily Traffic (AADT) |
| 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 |
|---|
| Date Range of Data Used: | 2012 to 2016 |
| Municipality: | |
| State: | IA |
| Country: | USA |
| Type of Methodology Used: | Regression cross-section |
| Sample Size (miles): | 1247 miles |
| Sample Size (mile-years): | 6235 mile-years |
| Other Details |
|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Jul 26, 2019 |
| Comments: | Non-animal crashes. CMF for changing access point spacing greater than 1320ft to 150ft or less. |
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