01518924

Component

https://doi.org/10.3141/2435-09

http://scholar.google.com...aran&publication_year=2014

Safety performance functions (SPFs) are crash prediction models that quantitatively relate the expected number of crash counts with traffic volume and roadway and roadside geometries. SPFs help traffic safety officials identify unsafe locations and take appropriate counteractive measures. A study assembled crash and roadway geometry data of freeways (only Interstate highway data were used for this study) in Connecticut for development of SPFs. Models were estimated separately for single-vehicle and multivehicle crashes. Total and fatal and injury crashes were considered for model estimation for both single-vehicle and multivehicle crashes. For each crash category, three model estimations were performed with negative binomial distribution models with all geometric variables, with speed limit only, and with interaction between speed limit and roadway geometric variables. The best models were selected for each crash category through a comparison of goodness-of-fit measures (Akaike information criterion). Interaction models were found to be the best models for all crash categories. This finding suggests the importance of incorporating the interaction effect between variables, in particular between speed limit and geometric variables such as number of lanes, shoulder width, and median type, for estimation of crash prediction models.

01543434

14-2933

English

pp 72–81

2014

Transportation Research Record: Journal of the Transportation Research Board

9780309295246

Print

References (17) ; Tables (11)

Crash risk forecasting; Freeways; Geometric design; Highway safety; Mathematical prediction; Speed limits; Traffic volume

Safety Performance Functions

Connecticut

Highways; Safety and Human Factors; I80: Accident Studies

PRP, TRIS, TRB, ATRI

Jan 27 2014 3:00PM

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• Safety Evaluation of Hybrid Main-Line Toll Plazas
• Transferability of the Highway Safety Manual Freeway Model to the Italian Motorway Network
• Use of Monte Carlo Simulation for a Sensitivity Analysis of Highway Safety Manual Calibration Factors
• Variable Speed Limit Control Strategy with Collision Probability Assessments Based on Traffic State Prediction