Role of Exposure in Analysis of Road Accidents

Exposure is a key variable in traffic safety research. In the literature, it is noted as the first and primary determinant of traffic safety. In many cases, however, no valid exposure measure is available. In Belgium, monthly traffic counts for 12 years are available. This offers the opportunity to investigate the added value of exposure in models, next to legal, economic, and climatologic variables. Multiple regression with autoregressive moving average (ARMA) errors is used to quantify the impact of these factors on aggregated traffic safety. For each dependent variable, a model with and without exposure is constructed. The models show that exposure is significantly related to the number of accidents with persons killed and seriously injured and to the corresponding victims, but not to the lightly injured outcomes. Moreover, the addition or deletion of exposure does not influence the effects of the remaining variables in the model. The effects of exposure clearly depend on the type of measure used and on the time horizon considered. The framework of a regression model with ARMA errors allows for missing variables being accounted for by the error term. Even without a variable such as exposure, valid models can be constructed.

[1]  A S Hakkert,et al.  A critical review of macro models for road accidents. , 1989, Accident; analysis and prevention.

[2]  Marc J.I. Gaudry,et al.  Structural Road Accident Models , 2000 .

[3]  S. Lassarre,et al.  The TAG-l Model for France , 2000 .

[4]  Geert Wets,et al.  A Regression Model with ARMA Errors to Investigate the Frequency and Severity of Road Traffic Accidents , 2003 .

[5]  Marc Gaudry,et al.  THE SNUS-2.5 MODE FOR GERMANY. IN: STRUCTURAL ROAD ACCIDENT MODELS. THE INTERNATIONAL DRAG FAMILY , 2000 .

[6]  Jean-Paul Hubert,et al.  La mobilite quotidienne des belges. , 2002 .

[7]  Donald W. Marquaridt.  Generalized Inverses, Ridge Regression, Biased Linear Estimation, and Nonlinear Estimation , 1970 .

[8]  R Kulmala,et al.  Measuring the contribution of randomness, exposure, weather, and daylight to the variation in road accident counts. , 1995, Accident; analysis and prevention.

[9]  Steven C. Wheelwright,et al.  Forecasting: Methods and Applications, 3rd Ed , 1997 .

[10]  Ronald W. Michener,et al.  A Poisson Regression Model of Highway Fatalities , 1992 .

[11]  J. Ledolter,et al.  Evaluating the Impact of the 65 mph Maximum Speed Limit on Iowa Rural Interstates , 1996 .

[12]  Sylvain Lassarre,et al.  THE TAG-1 MODEL FOR FRANCE. IN: STRUCTURAL ROAD ACCIDENT MODELS. THE INTERNATIONAL DRAG FAMILY , 2000 .

[13]  M. A. Wincek.  Forecasting With Dynamic Regression Models , 1993 .

[14]  Steven C. Wheelwright,et al.  Forecasting methods and applications. , 1979 .

[15]  Patrick Mccarthy.  The TRACS-CA Model for California , 2000 .

[16]  Francois Fournier,et al.  The DRAG-2 Model for Quebec , 2000 .

[17]  M. Gaudry,et al.  The Snus-2.5 Model for Germany , 2000 .

[18]  P Johansson,et al.  Speed limitation and motorway casualties: a time series count data regression approach. , 1996, Accident; analysis and prevention.

[19]  Marc Gaudry,et al.  TURNING BOX-COX INCLUDING QUADRATIC FORMS IN REGRESSION. IN: STRUCTURAL ROAD ACCIDENT MODELS. THE INTERNATIONAL DRAG FAMILY , 2000 .

[20]  Geert Wets,et al.  A regression model with ARIMA errors to investigate the frequency and severity of road traffic accidents. , 2004 .

[21]  Alan Pankratz,et al.  Forecasting with Dynamic Regression Models: Pankratz/Forecasting , 1991 .

[22]  Robert Simard,et al.  THE DRAG-2 MODEL FOR QUEBEC. IN: STRUCTURAL ROAD ACCIDENT MODELS. THE INTERNATIONAL DRAG FAMILY , 2000 .

[23]  W. W. Muir,et al.  Regression Diagnostics: Identifying Influential Data and Sources of Collinearity , 1980 .

[24]  I. Holmberg,et al.  The DRAG-Stockholm-2 Model , 2000 .

[25]  S Oppe,et al.  Macroscopic models for traffic and traffic safety. , 1988, Accident; analysis and prevention.

[26]  The TRULS-1 Model for Norway , 2000 .

[27]  Arthur C. Wolfe,et al.  THE CONCEPT OF EXPOSURE TO THE RISK OF A ROAD TRAFFIC ACCIDENT AND AN OVERVIEW OF EXPOSURE DATA COLLECTION METHODS , 1982 .

[28]  I. Holmberg,et al.  THE DRAG-STOCKHOLM-2 MODEL. IN: STRUCTURAL ROAD ACCIDENT MODELS. THE INTERNATIONAL DRAG FAMILY , 2000 .

[29]  Patrick McCarthy.  THE TRACS-CA MODEL FOR CALIFORNIA. IN: STRUCTURAL ROAD ACCIDENT MODELS. THE INTERNATIONAL DRAG FAMILY , 2000 .