CMF / CRF Details
CMF ID: 4016
Convert frontage road from two-way operation to one-way operation
Description:
Convert frontage road from two-way operation to one-way operation
Prior Condition: frontage road with two-way operation
Category: Access management
| Crash Modification Factor (CMF) |
|---|
| Value: | 0.46 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Crash Reduction Factor (CRF) |
|---|
| Value: | 54 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Applicability |
|---|
| Crash Type: | All |
| Crash Severity: | C (possible injury) |
| Roadway Types: | Not Specified |
| Street Type: | |
| Minimum Number of Lanes: | |
| Maximum Number of Lanes: | |
| Number of Lanes Direction: | |
| Number of Lanes Comment: | |
| Crash Weather: | Not specified |
| Road Division Type: | |
| Minimum Speed Limit: | |
| Maximum Speed Limit: | |
| Speed Unit: | |
| Speed Limit Comment: | |
| Area Type: | Not specified |
| Traffic Volume: | |
| Average Traffic Volume: | 2996 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: | 1998 to 2007 |
| Municipality: | |
| State: | TX |
| Country: | U.S.A. |
| Type of Methodology Used: | Simple before/after |
| Sample Size (crashes): | 74 crashes before, 31 crashes after |
| Other Details |
|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Jun 04, 2012 |
| Comments: | This CMF is for non-PDO possible injury crashes from Table 4.9 (p. 53). “Possible injury” is not listed under crash severity. The CMF standard error was computed using the confidence interval given in Table 4.9 (p. 53): (CMF upper limit-CMF lower limit)/(2*1.96). The crash data consisted of records from 1998 to 2007 but excluded records from 2002 (p. 24). The study method was before-after with comparison group. Since this is not available on the list for study methodology, simple before-after was selected. The before and after sample sizes were computed using Table 4-5 (p. 48) which lists the annual crash frequency in the before and after periods and Table 3-4 (p. 36) which lists the duration of the before and after periods. The average ADT for the before and after period for each treatment site is given in Table 4-7 (p. 49); however, the overall average ADT for the treatment group is not provided. To compute the overall average ADT for the treatment group, a weighted average was taken using the treatment site average ADTs and the treatment site before and after period lengths listed in Table 3-4 (p. 36): 44*2200+60*1800+43*1800+60*2200+36*4600+60*5500+36*2600+60*3200/(44+60+43+60+36+60+36+60)=2996 |
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