Abstract:
Road accidents have become a leading cause of death and injury as well as property damage
worldwide. In Sri Lanka, a steady increase of road accidents has been reported resulting in a rising
trend of fatalities too. In 2006, there were 2069 fatalities, while 2263 fatalities were reported in 2010.
There are a number of factors that increase the risk of road accidents, including vehicle design, speed
of operation, road design, road environment, driver’s skill and driver’s behaviour. The objective of
this study is to find the factors that mostly contribute to fatal road accidents caused by motor vehicle
drivers, using Logistic Regression Analysis.
This study investigates the factors affecting fatalities in road accidents in the Peliyagoda Police Area
in Gampaha district, using Logistic Regression Analysis. Accident data [519 accidents] recorded at
the Peliyagoda Police Station in 2009 were considered. A total number of 506 road accidents where
the motor vehicles were at fault were included in the analysis.
Based on the data obtained from the police records, several predictor variables were employed in
three independent Logistic Regression models in this study. A multinomial logistic model was used in
one of them to deal with the multiple nature of dependent variables such as fatal, grievous, non
grievous compared to damage only accidents. A binary logistic regression model was also developed
to evaluate the odds of fatal accidents compared to non fatal accidents. The odds of an accident being
fatal due to the collisions with pedestrians were high in both models with a positive effect. Since there
were only 17 fatal accidents (3.4%), both these models were unsuccessful with huge coefficients.
Re-categorizing fatal, grievous and non grievous accidents as human damage accidents, and damage
only accidents as non human damage accidents, a binary logistic regression model was constructed.
Head on crashes, approaching crashes, rear end crashes, crashes in conjunction with turning
movements, crashes with pedestrians and passengers were positively related to human damage
accidents rather than single crashes. Similarly, in the first two models, crashes with pedestrians and
passengers had high impact on increasing the odds of human damage accidents. The odds of an
accident being human damage were increased by a factor of 6.888 by having no traffic control rather
than having police traffic control. The odds of an accident being human damage by a driver/rider with
a valid or probationary driving license were about 25% and 13% respectively, lower than for
accidents caused by the drivers/riders without valid license.
The odds of an accident being human damage rather than being non-human damage are increased by a
factor of 6.742 for motor cycles and bicycles rather than heavy vehicles. For every one-unit increase
in the age of the vehicle, we can expect a 1.074 increase in the odds of human damage accidents,
holding all other independent variables constant. In the Peliyagoda Police area, analyzing human
damage accidents is more effective than analysing fatal accidents. However, a further study is
recommended for an area where fatal accidents are more significant.