CMF / CRF Details

CMF ID: 10208

Change from standard sized lanes to undersized lanes

Description: Convert from standard sized lanes (average lane width between 3.25 meters and 3.75 meters) to undersized lanes (average lane width less than 3.25 meters)

Prior Condition: Average lane width is between 3.25 meters and 3.75 meters

Category: Roadway

Study: Relationship between Lane Width and Safety along Urban Expressways in Shanghai, Wu et al., 2019

Star Quality Rating: 3 Stars   [View score details]
Rating Points Total: 95
Crash Modification Factor (CMF)
Value: 2.904
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value: -190.374   (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Type: All
Crash Severity: All
Roadway Types: Principal Arterial Other Freeways and Expressways
Street Type:
Minimum Number of Lanes: 4
Maximum Number of Lanes: 8
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather: Not specified
Road Division Type: Divided by Median
Minimum Speed Limit: 80
Maximum Speed Limit: 80
Speed Unit: km/h
Speed Limit Comment:
Area Type: Urban
Traffic Volume: Minimum of 42785 to Maximum of 120001 Average Daily Traffic (ADT)
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: 2010 to 2013
Municipality: Shanghai
Country: China
Type of Methodology Used: Regression cross-section
Sample Size (crashes): 50069 crashes
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Dec-07-2019
Comments: This CMF applies for expressway segments between interchanges.