As congestion on two-lane rural roads increases, there is increasing interest in conversion to a four-lane undivided or four-lane divided facility within the same corridor. There is a surprising lack of research aimed at precisely estimating the safety benefits of these conversions. This lack is due in large part to the difficulty of conducting such research, because the best answer would result from analysis of a large sample of converted locations covering many different before-and-after configurations. The authors have attempted to estimate the benefits of such conversions by developing cross-sectional models producing crash rates for typical sections of two- and four-lane roadways in four different states. Predicted crash reductions for conversion from most typical two- to four-lane divided sections ranged from 40 to 60 percent. The reduction due to conversion to a four-lane undivided configuration is much less well defined, ranging from no effect to perhaps a 20 percent reduction. Continuing research needs include ( a) verification of the undivided four-lane results, ( b) additional information on the effects of driveways, ( c) estimates for higher levels of two-lane average daily traffic, ( d) expansion of the outcome variable to include crash severity, and ( e) verification of all results by before-and-after studies of actual conversions.


    Access

    Download

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Safety Effects of the Conversion of Rural Two-Lane to Four-Lane Roadways Based on Cross-Sectional Models


    Additional title:

    Transportation Research Record


    Contributors:


    Publication date :

    1999-01-01




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English