CMF / CRF Details

CMF ID: 3852

Convert diamond interchange to Diverging Diamond Interchange (DDI) or Double Crossover Diamond (DCD)

Description: Convert a diamond interchange to a Diverging Diamond Interchange (DDI) or a Double Crossover Diamond (DCD)

Prior Condition: Diamond interchange

Category: Interchange design

Study: Diverging Diamond Interchange Performance Evaluation (I-44 & Route 13), Chilukuri et al., 2011

 
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Crash Modification Factor (CMF)
Value: 0.54
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value: 46   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:
Applicability
Crash Type: All
Crash Severity: All
Roadway Types: Principal Arterial Interstate
Number of Lanes:
Road Division Type: Divided by Median
Speed Limit:
Area Type: Urban
Traffic Volume:
Average Traffic Volume:
Time of Day: All
If countermeasure is intersection-based
Intersection Type: Roadway/roadway (interchange ramp terminal)
Intersection Geometry: 4-leg
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: 2004 to 2010
Municipality: Springfield
State: MO
Country: U.S.A.
Type of Methodology Used: Simple before/after
Sample Size (crashes): 519 crashes before, 56 crashes after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Jun-04-2012
Comments: The authors computed the CMF using the crash rates from Table S-5 (p. 18). The before and after sample sizes were taken from Table S-1 (p. 16).