CMF / CRF Details
CMF ID: 5535
Shorten left turn lane by X percent at unsignalized median opening
Description:
Shorten left turn lane by X percent shorter than the Greenbook recommended length at unsignalized median openings.
Prior Condition: Turn lane X percent different than Greenbook recommended length
Category: Access management
| Crash Modification Factor (CMF) |
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| Value: | .png) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Crash Reduction Factor (CRF) |
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| Value: | .png) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Applicability |
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| Crash Type: | Fixed object,Rear end,Sideswipe |
| Crash Severity: | All |
| Roadway Types: | Not specified |
| Street Type: | |
| Minimum Number of Lanes: | 4 |
| 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: | 30 |
| Maximum Speed Limit: | 40 |
| Speed Unit: | mph |
| Speed Limit Comment: | |
| Area Type: | Urban |
| Traffic Volume: | Minimum of 6600 to Maximum of 64800 Average Daily Traffic (ADT) |
| 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 |
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| Date Range of Data Used: | 2006 to 2011 |
| Municipality: | Houston |
| State: | TX |
| Country: | USA |
| Type of Methodology Used: | Regression cross-section |
| Sample Size (crashes): | 32 crashes |
| Sample Size (sites): | 52 sites |
| Sample Size (site-years): | 312 site-years |
| Other Details |
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| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Aug 12, 2014 |
| Comments: | In the CMFunction, X is the percentage shorter than the Greenbook recommended length. Values spanned from -47% (i.e., 47% shorter than the Greenbook length) to 38% (i.e., 38% longer than the Greenbook length). Also, traffic volumes ranged from 1639 vpdpl to 10,805 vpdpl. |
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