CMF / CRF Details

CMF ID: 9380

Implement truck lane restrictions

Description: TLR prohibit semi- trucks (trucks) from using the left-5 most freeway lane, or inner lane, except in passing or emergency maneuvers.

Prior Condition: Roadway without Traffic Lane Restrictions

Category: Roadway

Study: Safety Performance of Truck Lane Restrictions in Texas: Empirical Bayes Observational Before-After Analysis, Das et al., 2018

Star Quality Rating: 2 Stars   [View score details]
Rating Points Total: 65
Crash Modification Factor (CMF)
Value: 1.17
Adjusted Standard Error:
Unadjusted Standard Error: 0.36623
Crash Reduction Factor (CRF)
Value: -17   (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 36.623
Crash Type: Truck related
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types: Not specified
Street Type:
Minimum Number of Lanes: 8
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:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:
Traffic Volume:
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: 2011 to 2015
Municipality: Dallas-Fort Worth
State: TX
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (sites): 16 sites before, 16 sites after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Oct-27-2018
Comments: This CMF is for large truck involved fatal and injury crashes on eight-lane roadways. The number of crashes in the after period were not reported in this study, however, they have been recorded as 300 to give 10 points as a beneift of doubt for one or more of the following: (1) number of miles/sites in the reference/treatment group, (2) number of crashes in the references/treatment group, (3) reporting AADTs for the aggregate dataset but not for the disaggragate dataset used for CMF development.