CMF / CRF Details

CMF ID: 10584

Change speed limit

Description: Change speed limit from X to Y

Prior Condition: No Prior Condition(s)

Category: Speed management

Study: Developing crash modification factors for roundabouts using a cross-sectional method, Al-Marafi et al., 2020


Star Quality Rating:	[View score details]
Rating Points Total:	70

Crash Modification Factor (CMF)
Value:
Adjusted Standard Error:
Unadjusted Standard Error:

Crash Reduction Factor (CRF)
Value:
Adjusted Standard Error:
Unadjusted Standard Error:

Applicability
Crash Type:	All
Crash Severity:	K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types:	Not specified
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:
Minimum Speed Limit:	40
Maximum Speed Limit:	70
Speed Unit:	km/h
Speed Limit Comment:
Area Type:	Urban
Traffic Volume:
Average Traffic Volume:
Time of Day:
If countermeasure is intersection-based
Intersection Type:	Roadway/roadway (not interchange related)
Intersection Geometry:	Not specified
Traffic Control:	Roundabout
Major Road Traffic Volume:	Minimum of 1288 to Maximum of 16071 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:	Minimum of 1200 to Maximum of 10002 Annual Average Daily Traffic (AADT)
Average Major Road Volume :	6966 Annual Average Daily Traffic (AADT)
Average Minor Road Volume :	4341 Annual Average Daily Traffic (AADT)

Development Details
Date Range of Data Used:	2010 to 2015
Municipality:	Toowoomba City
State:	notusa
Country:	Australia
Type of Methodology Used:	Regression cross-section
Sample Size (sites):	49 sites

Other Details
Included in Highway Safety Manual?	No
Date Added to Clearinghouse:	Dec 17, 2020
Comments:	CMFunction for speed limit (kph) on the major approach

View the Full Study Details

This site is funded by the U.S. Department of Transportation Federal Highway Administration
and maintained by the University of North Carolina Highway Safety Research Center

For more information, contact Sarah Weissman Pascual at sarah.pascual@dot.gov

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.

CRASH MODIFICATION FACTORS CLEARINGHOUSE