Abstract

The safety improvement project for a section of US 119 across Pine Mountain in Letcher County was initiated as an interim effort to address safety issues related to roadway geometrics and specific problems related to truck traffic. The project involves sections of the road being improved over a 7.2-mile length at a cost of approximately $36 million.

The Transportation Center at the University of Kentucky was requested to perform an evaluation of the safety improvement project on US 119 to determine whether the types of improvements undertaken have affected the overall safety of the roadway. Specific objectives were as follows; 1) to determine the effects of a ban on truck traffic that was implemented in March 2001, 2) to determine if the types of improvements undertaken as part of the project are applicable to other locations, and 3) to determine if the use of flexible design was successful by allowing the Transportation Cabinet to remove the truck restriction by permitting trucks with dimensions up to the WB-50 design to travel across the mountain and be able to track within their own lane. This interim report documents crash data prior to and after implementation of the truck ban and during construction.

The section of US 119 where the truck ban was placed had a crash rate of 430C/100MVM prior to the start of the truck ban with a critical rate factor (CRF) of 1.31 for this type of road and traffic volume. The adjacent section of US 119, which has a similar cross section but less grade and sharp curvature, had a rate of 161 C/100MVM which is less than the statewide average. The injury crash rate for the truck ban section was 91 C/100MVM which is almost identical to the statewide average. There were no fatal crashes in this section. About 61 percent of the crashes in this section have involved a truck (compared to a statewide percentage of about 7 percent). Over the study period about 59 percent of the truck crashes have involved an opposite direction sideswipe with about 37 percent a single vehicle crash. The truck ban reduced the total number of crashes by about 38 percent and the number of truck crashes by 55 percent in the two years after the start of the ban. The reductions in the first year after the start of the reconstruction, along with the truck ban, were 62 percent in total crashes and 86 percent in truck crashes. There have been 15 truck crashes in the truck ban section after the start of the ban with 10 involving an out-of-state driver. The locations with the highest number of truck crashes were at locations with a sharp curve.

Report Date

10-2003

Report Number

KTC-03-34/FR121-02-1I

Digital Object Identifier

http://dx.doi.org/10.13023/KTC.RR.2003.34

Notes

The contents of this report reflect the views of the authors, who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the University of Kentucky or the Kentucky Transportation Cabinet. This report does not constitute a standard, specification, or regulation. The inclusion of manufacturer names or trade names is for identification purposes only and is not to be considered an endorsement.

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