CMF / CRF Details

CMF ID: 2482

Increase freeway on-ramp density from 0 to 5 ramps per mile on tangents

Description: The ramp density is the number of on-ramps per mile (total in both directions)

Prior Condition:  No Prior Condition(s)

Category: Access management

Study: Evaluating the Effects of Freeway Design Elements on Safety, Park, Fitzpatrick, Lord, 2010

Star Quality Rating:4 Stars  [View score details]
Rating Points Total:110
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.098
Crash Reduction Factor (CRF)
Value:-11.9  (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:9.8
Crash Type:All
Crash Severity:K (fatal),A (serious injury),B (minor injury),C (possible injury)
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:All
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
Date Range of Data Used:1997 to 2001
Type of Methodology Used:Regression cross-section
Sample Size (crashes):4980 crashes
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Jan 01, 1970