Linking Roadway Geometrics and Real-Time Traffic Characteristics to Model Daytime Freeway Crashes: Generalized Estimating Equations for Correlated Data
- 1 January 2004
- journal article
- research article
- Published by SAGE Publications in Transportation Research Record: Journal of the Transportation Research Board
- Vol. 1897 (1), 106-115
- https://doi.org/10.3141/1897-14
Abstract
A model was developed to predict daytime crashes on a freeway when real-time traffic flow characteristics and roadway geometric features are known. The data used were for 337 daytime crashes that occurred on Interstate 4 in 1999 in Orlando, Florida (13.25 mi), where corresponding loop detector traffic data were available up stream and downstream of the location of every crash and for at least 30 min before the crash occurred. The traffic data included average speed, volume, and occupancy rate for every 30 s at 0.5-mi intervals. Traffic characteristics for noncrash cases at the same locations and at similar times of the crash cases were extracted and fed to the model. The generalized estimating equations technique with binomial probit link function was used to account for correlation between crashes that occurred at the same location. Three different correlation structures (independent, exchangeable, autoregressive) were used, discussed, and compared. The modeling results showed that the existence of an on-ramp increases the likelihood of a crash within 0.5 mi downstream of the crash location. High variability in speed for a period of 15 min in a certain location was shown to increase the likelihood of a crash 0.5 mi downstream. Unlike speed, low variability in volume over 15 min was shown to increase the likelihood of a crash at 1 mi downstream.Keywords
This publication has 8 references indexed in Scilit:
- Predicting Freeway Crashes from Loop Detector Data by Matched Case-Control Logistic RegressionTransportation Research Record: Journal of the Transportation Research Board, 2004
- Categorical Data AnalysisWiley Series in Probability and Statistics, 2002
- Case–Control Studies of Association in Structured or Admixed PopulationsTheoretical Population Biology, 2001
- Effect of roadway geometrics and environmental factors on rural freeway accident frequenciesAccident Analysis & Prevention, 1995
- The relationship between truck accidents and geometric design of road sections: Poisson versus negative binomial regressionsAccident Analysis & Prevention, 1994
- An analysis of truck-involved freeway accidents using log-linear modelingJournal of Safety Research, 1987
- Longitudinal data analysis using generalized linear modelsBiometrika, 1986
- Generalized Linear ModelsJournal of the Royal Statistical Society. Series A (General), 1972