01478092

Component

https://doi.org/10.3141/2398-10

http://scholar.google.com...+Gan&publication_year=2013

The empirical Bayes approach adopted in the Highway Safety Manual and the SafetyAnalyst software application require the use of safety performance functions (SPFs). SafetyAnalyst adopts a form of SPF, known as the simple SPF, that relates crash experience to traffic volume only. It is a flow-only model that is calibrated by using all sites irrespective of their base geometric conditions. Full SPFs, however, relate crash occurrence to roadway geometric characteristics in addition to traffic characteristics. This study compared the simple SPFs provided in SafetyAnalyst with full SPFs in two safety applications: crash prediction performance and identification of high-crash locations. To compare the prediction performance, the simple and full SPFs were estimated with data collected on urban four-lane freeway interchange influence areas in Florida. Models were estimated for both total crashes and fatal and injury crashes. The mean absolute deviance and the mean square prediction error were used to assess and compare the prediction performance of the two models, and the variation in ranking the high-crash locations with each model was also examined. The results showed that the two models yielded very similar performance of crash prediction and network screening. This empirical result supports the use of the flow-only SPF model adopted in SafetyAnalyst, whose development requires much less effort compared with that for full SPFs.

01521593

13-4828

English

pp 83–92

2013

Transportation Research Record: Journal of the Transportation Research Board

9780309294881

Print

Figures (2) ; References (37) ; Tables (7)

Crashes; Data collection; Four lane highways; Freeways; High risk locations; Traffic characteristics; Traffic volume

Highway Safety Manual; Safety Performance Functions; SafetyAnalyst (Software)

Empirical Bayes method; Safety performance functions

Florida

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

TRIS, TRB, ATRI

Feb 5 2013 12:56PM

• Calibration and Development of Safety Performance Functions for Alabama: Two-Lane, Two-Way Rural Roads and Four-Lane Divided Highways
• Development of Relationships Between Safety and Congestion for Urban Freeways
• Estimating Annual Average Daily Traffic for Local Roads for Highway Safety Analysis
• Influence of Land Use and Driveway Placement on Safety Performance of Arterial Highways
• Safety Effects of Horizontal Curve and Grade Combinations on Rural Two-Lane Highways
• Safety Evaluation of Converting Traffic Signals from Incandescent to LED Bulbs (with Discussion and Closure)
• Safety Evaluation of Discontinuing Late Nighttime Flash Operations at Signalized Intersections
• Safety of Channelized Right-Turn Lanes for Motor Vehicles and Pedestrians
• Safety Performance Functions Reflecting Categorical Impact of Exposure Variables for Freeways
• Severity Distribution Functions for Freeway Segments
• Spatial Effects on Zone-Level Collision Prediction Models