01123191

Component

Agencies are seeking a better understanding of those roadway or roadside features that affect safety. The objectives of this study were to develop a horizontal curve accident modification factor (AMF) for rural, four-lane divided and undivided highways and to determine if the effect of driveway density is different for horizontal curves as compared to tangent sections. Data available for use in the evaluation included 121 centerline miles of rural, four-lane highways. Negative binomial regression models were used to determine the effects of independent variables on crashes. Variables considered in developing the base models included driveway density, lane width, outside shoulder width, median width (which included inside shoulder width), median type, degree of curve, segment length, and average daily traffic. Five years (1997-2001) of driveway and segment crashes were examined. An AMF for horizontal curves was estimated and it supports a theoretical model developed in another study. Reviewing the findings with respect to driveway density revealed that the effect of driveway density is different for horizontal curves and tangents; however, the differences were relatively minor. Therefore, the driveway density AMF determined using both the horizontal curve and tangent sections is recommended.

01120148

09-0204

English

22P

2009

Transportation Research Board 88th Annual Meeting

DVD

Figures (2) ; References (26) ; Tables (6)

Crash modification factors; Divided highways; Driveways; Four lane highways; Highway curves; Rural highways; Safety; Traffic safety

Horizontal curvature; Undivided highways

Texas

Highways; Safety and Human Factors; I82: Accidents and Transport Infrastructure

Transportation Research Board Annual Meeting 2009 Paper #09-0204

TRIS, TRB

Jan 30 2009 4:30PM