CMF / CRF Details
CMF ID: 8872
Implement systemic signing and marking improvements at stop-controlled intersections
Description:
Double‐up (i.e., both right and left side) 36 in. x 36 in. intersection warning signs (W2- 22 series in the MUTCD (4)) on fluorescent yellow sheeting.
Add advance street name plaque (W16‐8 in the MUTCD(4)) on fluorescent yellow 24 sheeting accompanying each right‐side intersection warning sign.
Double-up (i.e., both right and left side) 48 in. x 48 in. STOP or YIELD signs (R1‐1 and 26 R1‐2 in the MUTCD(4)). Install retroreflective strips on sign posts for the above signs.
Place minor road stop bars within 4 to 10 ft of the edge of the nearest through lane along the major road.
Install yield bars at all lanes having yield conditions.
Add dashed white edge-lines along the major road through the intersection.
Remark all existing stop bars, crosswalks, arrows and word messages unless:
o The roadway has been resurfaced within one calendar year and new thermoplastic markings have been applied.
o Existing markings are uniformly reflective and above ground thickness is 90 mils or greater.
o Otherwise directed by a district representative.
Mark all turn lanes to include the pattern of lane arrows and text marking “ONLY” based on the turn lane length.
Prior Condition: Stop-controlled intersections without systemic signing and marking improvements
Category: Intersection traffic control
| Crash Modification Factor (CMF) |
|---|
| Value: | 0.748 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.022 |
| Crash Reduction Factor (CRF) |
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| Value: | 25.2 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 2.2 |
| Applicability |
|---|
| Crash Type: | All |
| Crash Severity: | All |
| Roadway Types: | All |
| Street Type: | |
| Minimum Number of Lanes: | 2 |
| Maximum Number of Lanes: | 4 |
| 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: | Rural |
| Traffic Volume: | |
| Average Traffic Volume: | |
| Time of Day: | All |
| If countermeasure is intersection-based |
| Intersection Type: | |
| Intersection Geometry: | 3-leg,4-leg |
| Traffic Control: | Stop-controlled |
| Major Road Traffic Volume: | Minimum of 641 to Maximum of 41731 Annual Average Daily Traffic (AADT) |
| Minor Road Traffic Volume: | Minimum of 102 to Maximum of 8436 Annual Average Daily Traffic (AADT) |
| Average Major Road Volume : | 11042 Annual Average Daily Traffic (AADT) |
| Average Minor Road Volume : | 1453 Annual Average Daily Traffic (AADT) |
| Development Details |
|---|
| Date Range of Data Used: | 2005 to 2014 |
| Municipality: | |
| State: | SC |
| Country: | |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (sites): | 245 sites before, 245 sites after |
| Other Details |
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| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Nov 17, 2017 |
| Comments: | The number of crashes in the after period were not reported in this study, however, they have been recorded as 300 to give 10 points as a beneift of doubt for one or more of the following: (1) number of miles/sites in the reference/treatment group, (2) number of crashes in the references/treatment group, (3) reporting AADTs for the aggregate dataset but not for the disaggragate dataset used for CMF development. |
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