CMF / CRF Details

CMF ID: 298

Increase intersection median width by 3 ft increments


Prior Condition: No Prior Condition(s)

Category: Access management

Study: NCHRP Report 375: Median Intersection Design, Harwood et. al, 1995

Star Quality Rating: 5 Stars
Crash Modification Factor (CMF)
Value: 0.96
Adjusted Standard Error: 0.02
Unadjusted Standard Error: 0.01
Crash Reduction Factor (CRF)
Value: 4   (This value indicates a decrease in crashes)
Adjusted Standard Error: 2
Unadjusted Standard Error: 1
Crash Type: Multiple vehicle
Crash Severity: All
Roadway Types: Not Specified
Number of Lanes:
Road Division Type:
Speed Limit:
Area Type: Rural
Traffic Volume:
Average Traffic Volume:
Time of Day:
If countermeasure is intersection-based
Intersection Type: Roadway/roadway (not interchange related)
Intersection Geometry: 4-leg
Traffic Control: Stop-controlled
Major Road Traffic Volume:
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:
Type of Methodology Used: Regression cross-section
Other Details
Included in Highway Safety Manual? Yes. HSM lists this CMF in bold font to indicate that it has the highest reliability since it has an adjusted standard error of 0.1 or less. However, it also includes a caret (^) notation to indicate that the CMF value itself is within the range 0.90 to 1.10 but that the left-hand side or the right-hand side of the confidence interval defined by the CMF ± two times the standard error may be exactly at 1.0. This is important to note since a treatment with such an AMF may result in no change in safety. HSM recommends using this CMF with caution.
Date Added to Clearinghouse: Dec-01-2009
Comments: Countermeasure name changed to match HSM