Investigation of road accidents on the Jamuna bridge and its approach roads

Abstract

In this investigation an attempt has been made to depict the accident scenario on JMB and its approach roads with a special aim to find out the underlying causes of various accidents with a view to suggest appropriate corrective measures. This also considers evaluating the performances of safety measures that have been implemented along this corridor in 2001. The investigation comprises a total length of 36.1 km of the JMB and its approach roads which passes through Bhuapur thana of Tangail District and Belkuchi thana of Sirajgon District. Accident data used in this study is collected and recorded by JOMAC during the period of 01 Jan 99 to 31 Mar 04. Followings are the major findings of accident characteristics analysis: •• Hourly distribution of accident shows that maximum accidents are occurred between 4.00 to 7.00 hrs, 10.00 to 12.00 hrs and 15.00 to 16.00 hrs respectively. From the analysis of weekly accident pattern, no significant variation is observed throughout the week. December month is found to be the worst month with 11.94% accidents. • Data shows that 59.81% accident occurred during daytime. No significant effect of bad weather on accident occurrence is found. Nearly 70% accident happened at fine weather condition. Road surface condition data reveals that 87% and 12% accidents occurred at dry and wet condition respectively. • Out of 10lO accidents 83.27% occurred at or within 20m of junction. Among the junctions, the roundabouts are found to be most dangerous type of intersection. • Truck and buses caused 48% and 27% of accidcnts respectively. It is also found that 7.37% vehicle involved in accidents had no registration number. • 78.34% accidents occurred due to competition attitude of drivers followed by at time of parking (18%), stopping (18%), making right turn (16%) and over speeding (22%) respectively. • Analysis of different accident contributory factors it is revealed that road users, vehicle and road are responsible for 84.32%, 11.78% and 3.68% accidents respectively. Moreover, close observation of vehicle factor related accidents shows that 15.65% accidents occurred due to defective brakes, 5.21% due to defective steering, 71.3% due to defective tyres or wheels. • According to casualty class it is found that out of 1010 reported accidents 314 (13.85%) arc fatal, 985 (43.45%) are serious injury, 968 (42.69%) arc minor injury type. Among casualties 78%, 11%, and 8% arc passengers, drivcrs and pedestrian respectively. • Based on locational analysis it is found that 47.52% accidents occurred on West approach, 50.49% on East approach and 1.98% occurred on the main bridge. Before-after analysis of safety improvement measures shows that due to implementation of guard-posts at roundabout and speed breakers at few accident-prone sites, accident reduced by 14.49% even though speed breakers themselves induced few accidents. It is also evident that withdrawn of speed breakers in late 2002 the number of accidents started rising again. Following findings are obtained from black spot analysis: • It is found that along the 36.1 km highway, 81.18% of accidents occurred in clustered pattern. Considering a location is black spot if there is at least 12 accidents including 3 fatalities occurred during the study period, a total of 17 sites at West approach and 18 sites at East approach are identified as black spots. • From the dot diagram it is found that West Roundabout, East Roundabout, Kodder More (WI8), Slab bridge E18, Jogar Bazar Junction, Bhuapur Junction etc. are the most hazardous locations. It is also observed that all the narrow bridges/culverts are the major source of accident. • Data shows that 6.34% accidents occurred at East roundabout while 9.01% occurred at West roundabout. Analysis of data shows that most of the accidents occurred at both the roundabout are because of drivers faults like careless driving (32%, 37%), tired or sleep (15%, 8%), overspeeding (22%, 24%) etc. Considering the contributory factors in the occurrence of accidents it is found that the road users faults constitute 82% and 84% accidents at East and West Circle respectively. • Most striking finding is that at these roundabouts 32% and 67% accidents are occurred from direct hitting of the island. Time of occurrence of these accident shows that most of them happened in broad daylight. This revelation definitely suggests that most of the driver did not see the roundabouts before hitting. At the same time, it can be inferred that these drivers did not pay any attention to the advanced large sized roundabout signboard. • Moreover, it is also observed that at these East and West roundabouts 20% and 7% accidents are happened due to passenger fall down, which is obviously the consequence of high speed turning at the roundabouts. Economic analysis of accident data, based on World Bank 1997 unit costs, reveals that during 1999 - 2003 period on average per annum the nation has lost nearly Tk. 93.0 million due to accident occurring along 36.1 km segment of the highway and for the entire study duration the total loss is nearly Tk. 475.5 million. This economic loss would be much higher if it were calculated based on the current year unit costs. Finally, based on the research findings of this study, several site specific recommendations are made in order to further improve safety situation of JMB approach roads.