CMF / CRF Details

CMF ID: 8278

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: Safety Evaluation of Seven of the Earliest Diverging Diamond Interchanges Installed in the US, Hummer et al., 2016

 
Star Quality Rating: 4 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.59
Adjusted Standard Error:
Unadjusted Standard Error: 0.07
Crash Reduction Factor (CRF)
Value: 41 (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 7
Applicability
Crash Type: All
Crash Severity: Fatal,Serious injury,Minor injury
Roadway Types: Principal Arterial Other Freeways and Expressways
Number of Lanes: 3-6
Road Division Type: Divided by Median
Speed Limit: 40-45
Area Type: Suburban
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:
Development Details
Date Range of Data Used:
Municipality:
State: KY, MO, NY, TN
Country: USA
Type of Methodology Used: Before/after using comparison group
Sample Size (crashes): 340 crashes before, 110 crashes after
Sample Size (sites): 6 sites before, 6 sites after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Jan-17-2017
Comments: The volume here is the crossover volume. CMFs of six interchanges in MO, KY, NY, and TN.

[View the Full Study Details]

The information contained in the Crash Modification Factors (CMF) Clearinghouse is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in the CMF Clearinghouse. The information contained in the CMF Clearinghouse does not constitute a standard, specification, or regulation, nor is it a substitute for sound engineering judgment.