CMF / CRF Details
CMF ID: 3139
Convert a Type I exit ramp to a Type II exit ramp
Description:
Type I is a full width parallel from tangent that leads to either a tangent or flat exiting curve which includes a decelerating taper. The horizontal and vertical alignment of type I exit ramps were based on the selected design speed equal or less than the intersecting roadways.
Type II is when the outer lane becomes a drop lane at the exit gore forming a lane reduction. A paved and striped area beyond the theoretical gore were present at this type of exit ramps to provide a maneuver and recovery area.
Prior Condition: No Prior Condition(s)
Category: Interchange design
Crash Modification Factor (CMF) |
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Value: | 1.21 |
Adjusted Standard Error: | |
Unadjusted Standard Error: | 0.1 |
Crash Reduction Factor (CRF) |
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Value: | -21 (This value indicates an increase in crashes) |
Adjusted Standard Error: | |
Unadjusted Standard Error: | 10 |
Applicability |
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Crash Type: | Truck related |
Crash Severity: | All |
Roadway Types: | Principal Arterial Other Freeways and Expressways |
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: | Divided by Median |
Minimum Speed Limit: | |
Maximum Speed Limit: | |
Speed Unit: | |
Speed Limit Comment: | |
Area Type: | Not specified |
Traffic Volume: | |
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: | 2005 to 2008 |
Municipality: | |
State: | FL |
Country: | usa |
Type of Methodology Used: | Regression cross-section |
Sample Size (crashes): | 4630 crashes |
Other Details |
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Included in Highway Safety Manual? | No |
Date Added to Clearinghouse: | Jul 15, 2011 |
Comments: | |