Truck involvement in road accidents in metropolitan Dhaka

Abstract

Road safety is an important consideration in urban traffic planning and safety. Globally upto two thirds of all traffic injuries occur in urban areas, and trucks are significant in the overall context of road accidents. This thesis presents the results of a study of truck accident patterns and involvement in metropolitan Dhaka. Accident characteristics were examined in terms of severity level, locations, accident rates, accident types, accident clustering, vehicle factors, time of accidents, casualty class, costs and relationships between truck accidents and truck traffic characteristics (volume, composition and vehicle kilometers travel). Some striking deferring between truck and non-truck accidents are also identified. Analyses were based on 204 truck accidents out of 750 reported road accidents which occurred in three thanas (viz. Tejgaon, Mirpur and Mohammadpur) during the two year period, 1993-1994. There were 65 (32%) fatal, 101 (58%) injury and 18 (9%) property damage truck involved accidents. Trucks were greatly over represented (relative to both vehicle numbers involved in accidents and vehicle kilometers of travel) in accidents. Truck accidents occurred mostly on road links, 68.6 percent and the link problem further increases with a shift from the city center to the outskirts. Problem types were identified by disaggregating accidents into accident types using the event classified system of 'definition for coding accident (DCA) types.' The most frequent accident types were rear-end (DCA 31) (29%), hit pedestrian (DCA 00-09) (28%) and head-on (DCA 21) (10%) accidents. A statistical quality control method was employed to identify hazardous links. The road links between Farrngate and Kawran Bazar and between Darussalam Police Box to Gabtoli were determined as the hazardous links or blackspots, accounting for 8 percent and 15 percent of the link accidents respectively. Two intersections, Nine Division Crossing and Khejurbagan Crossing, were identified as high accident intersections accounting for 16 percent and 22 percent of the intersection accidents respectively. Fatal accidents were mostly attributed to single truck accidents involving pedestrians and grievous injuries to multi-vehicle truck accidents. Higher proportion of baby taxis and rickshaws were involved in truck accidents, each accounting for 21 percent. Around 41 percent of truck accidents occurred in the five hour period between 1100 and 1600 hrs. Trucks in accidents were particularly overinvolved in early morning (0100-0400 hrs.) and at midday during 1200-1400 hrs. Non truck accidents were relatively high during late hours at night (2200-2300 hrs.). The site analyses showed the incidence of clustering of truck accidents both at intersections and at links, 50 percent of the truck accidents occurred at 20 percent of the sites. The relationships between truck accidents and truck traffic characteristics have been examined and it was found that truck accidents are highly correlated with the percentage of trucks in the traffic stream and truck kilometers of travel. Analyses related to casualties showed that each year at least 35 fatalities and 105 injuries resulting in about 2.9 casualties per truck accidents in the study area. The most vulnerable user group was pedestrians (25.5%), followed by occupants of baby taxi (15.5%) and rickshaw (15.1%). The share of pedestrians was much more in non-truck accidents. Most of the truck accident victims tended to be young and middle aged in the 0-30 years age group, accounting for 81 percent (24% 0-10 years, 27% 11-20 years and 29% 21-30 years). In this study the average cost of damages per truck accident was estimated as Tk. 28,480/- (equivalent to US$ 695). Further aspects of truck accidents were examined by determining the application of Microcomputer Accident Analysis Package (MAAP) based on information collected by introducing new accident report form. The accident factors considered were road surface condition, road traffic control, weather condition, light condition, junction type, incidence of alcohol and maneuvering characteristics. The most striking findings from this analysis were that the most of the truck accidents occurred on dry surface, good weather condition and in the absence of traffic police. Nearly 14 percent of the truck drivers were intoxicated by the incidence of alcohol. By reviewing the findings of truck accident characteristics, potential possible cost-effective accident countermeasures related to engineering, enforcement and education have been discussed and areas of future research and investigations relating to road safety are identified.