CMF / CRF Details
CMF ID: 8334
Install an additional lane
Description: Use reducing lane and shoulder width to install additional lanes for urban freeway
Prior Condition: Freeway with fewer lanes
Category: Roadway
Study: Operational and Safety Trade-offs: Reducing Freeway Lane and Shoulder Width to Permit an Additional Lane, Dixon et al., 2016
| Star Quality Rating: |
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| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.76 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.092 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 24 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 9.2 |
| Applicability | |
|---|---|
| Crash Type: | All |
| Crash Severity: | K (fatal),A (serious injury),B (minor injury),C (possible injury) |
| Roadway Types: | Principal Arterial Other Freeways and Expressways |
| Number of Lanes: | 2-5 |
| Road Division Type: | Divided by Median |
| Speed Limit: | >50 |
| Area Type: | Urban |
| Traffic Volume: | Minimum of 200 to Maximum of 281450 Average Daily Traffic (ADT) |
| Average Traffic Volume: | 152163 Average Daily Traffic (ADT) |
| 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: | 2010 to 2013 |
| Municipality: | Dallas, Houston, San Antonio |
| State: | TX |
| Country: | USA |
| Type of Methodology Used: | Regression cross-section |
| Sample Size (crashes): | 407 crashes |
| Sample Size (sites): | 536 sites |
| Sample Size (site-years): | 2104 site-years |
| Other Details | |
|---|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Jan-17-2017 |
| Comments: | CMF applies to adding one additional lane with 11 ft average lane width |
