Turner-Fairbank Highway Research Center

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Accident Models for Two-Lane Rural Segments and Intersections

Product Type

Journal Article


Andrew Vogt and Joe Bared



Full citation

Andrew Vogt and Joe Bared. Accident Models for Two-Lane Rural Segments and Intersections, Transportation Research Record 1635, TRB, National Research Council, Washington D.C., 1998


Data collected from the states of Minnesota and Washington on rural two-lane highways are used to build accident models for segments and three-legged and four-legged intersections stop-controlled on the minor legs. The quantity, quality, and variety of data collected, together with the advanced techniques applied in the analysis, make this study of special interest. Variables include traffic, horizontal and vertical alignments, lane and shoulder widths, roadside hazard rating, channelization, and number of driveways. Models are of negative binomial and extended negative binominal form and yield R^2 values from 0.42 to 0.73 and overdispersion parameters from 0.20 to 0.51. A segment model combining both states and including states as a variable, and intersection model derived from Minnesota data, are featured, along with summary statistics, goodness-of-fit measures, and cross-validation between the states. Segment accidents depend significantly on most of the roadway variables collected, while intersection accidents depend primarily on traffic. The study recommends development of adjustment factors for different regions and times and further development of extended negative binomial models.

Available From

Transportation Research Record 1635

Link To Journal Article

Link not available.


Highway Safety
Accident Prediction Models
Two-Lane Rural Highways
Negative Binomial Model
Extended Negative Binomial Models
Highway Geometric Design

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