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Modeling Road Traffic Crashes Using Spatial-Autoregressive Model With Spatial – Autoregressive Disturbances


A simple spatial model considers spillover effects either in the dependent variable or in the disturbance term. When the focus is on the dependent variable, the spillover effects is modeled by including a right-hand-side variable known as a spatial lag. Each observation of the spatial-lag variable is a weighted average of the values of the dependent variable observed for the other cross-sectional units. The matrix containing the weights is known as the spatial-weighting matrix. This model is frequently referred to as a Spatial- Autoregressive (SAR) model. A generalized version of this model also allows for the disturbances to be generated by a SAR process. The combined SAR model with SAR disturbances is referred to as SARAR model. This paper examines Road Traffic Crashes (RTC) in Oyo State, Nigeria. The number of RTC in each Local Government Area (LGA) of the state was used as the dependent variable, while the explanatory variables include land area, population, major road lengths and travel densities corresponding to each LGA. The objective is to calculate predictions that were in turn used to calculate marginal effects on RTC. This study explored marginal changes by using the reduced form predictor and the observed values of the exogenous variables to obtain predicted values for RTC. The predicted effect of the change will be a 0.9% increase in RTC in Ibadan North East LGA. The mean predicted increase is less than 0.01% of the mean level of RTC in the contiguous LGAs. Less than 1% of the sample had any significant difference, with no change at all predicted for at least 95% of the LGAs. The framework should enable an understanding of the dynamics of RTC and enhance the orientation of safety and injury prevention policies.

Corporate Author: 
Ethipian Economics Association (EEA)
Ethipian Economics Association (EEA)
Primary Descriptors: 

Run-off-the-road accidents

Secondary Descriptor: 

Traffic Accident

Cataloge Date: 
Broad Subject heading: 
Road Crashes
Call Number: 
330.963 PRO 2015
Serial Key Title: 
Proceedings of the 19th Annual Conference of Africa Region Chapter of the Econometric Society
Publication catagory: 
Content type: 
Publication date: 
2015-06-01 00:00:00
Conference Place: 
EEA Conference Center
Place of publication: 
Addis Ababa, Ethiopia
Type of material: 
Current frequency: 
Conference date: 
July 16 to 19, 2014