CMF / CRF Details

CMF ID: 9

Five to six lane conversion

Description:

Prior Condition: No Prior Condition(s)

Category: Roadway

Study: Safety Effects of Using Narrow Lanes and Shoulder-Use Lanes to Increase the Capacity of Urban Freeways , Bauer et al., 2004

 
Star Quality Rating: 3 Stars
Crash Modification Factor (CMF)
Value: 1.07
Adjusted Standard Error:
Unadjusted Standard Error: 0.07
Crash Reduction Factor (CRF)
Value: -7   (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 7
Applicability
Crash Type: All
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types: Principal Arterial Other Freeways and Expressways
Number of Lanes: 5 (one way)
Road Division Type:
Speed Limit:
Area Type: Urban
Traffic Volume: Minimum of 77000 to Maximum of 126000 Average Daily Traffic (ADT)
Average Traffic Volume:
Time of Day:
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:
Municipality:
State:
Country:
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Other Details
Included in Highway Safety Manual? Yes. HSM lists this CMF in bold font to indicate that it has the highest reliability since it has an adjusted standard error of 0.1 or less. However, it also includes an asterisk (*) to indicate that the CMF value itself is within the range 0.90 to 1.10, but that the confidence interval defined by the CMF ± two times the standard error may contain the value 1.0. This is important to note since a treatment with such an CMF could potentially result in (a) a reduction in crashes (safety benefit), (b) no change, or (c) an increase in crashes (safety disbenefit). HSM recommends that this CMF should be used with caution.
Date Added to Clearinghouse: Dec-01-2009
Comments: AADT is one direction