Performance evaluation of road safety measures in Dhaka-Aricha highway

Abstract

In this study an attempt has been made to depict the accident scenario and evaluate the performances of safety features that have been installed along Dhaka-Aricha highway, during 1990 - 2003 observation periods. The study comprises a total length of 75.4 km of the nationally important Dhaka-Aricha highway corridor which passes through six Upazilas, namely Savar, Dhamrai, Saturia, Manikganj, Ghior and Shibalaya. Data were collected both 'before' and 'after' implementation of safety improvement works undertaken along this highway. Accident data were directly retrieved from the Police records viz. FIR and Crime Index Register; data were also collected from the Hospital Road Traffic accident (RTA) register and Road Safety Cell (RSC) for verification purposes. Performance evaluation of safety measures is made by applying before-after technique, control-site method and standard statistical chi-square method. Economic assessment of black-spot improvement works is also carried out to see the effectiveness in monetary terms. Findings of accident data recording/reporting, analysis and performance evaluation of safety measures are summarized bellow: General Analysis of Accident Data Q In this corridor nearly 45% of total recorded accident data and 48% of fatal data are not reported to the road safety cell (RSC) by the police. In most of the accident events response time of police to the incidence is not prompt and police fills up the accident form much later after the actual incidence. Q During the study period total 1922 accidents occurred of which I 147 (60%) are fatal, 551 (28%) are grievous, 129 (7%) are simple and 95 (5%) are property damage (PO) type accident. Q Among six UZs, the Savar UZ experienced the highest number of accidents (902, 47%) followed by Dhamrai (290,15%), Manikganj (251,13%), Shibalaya (230,125), Ghior (151,8%) and Saturia (98, 5%) UZ. Ghior UZ has the highest severity index of 0.97; followed by Dhamrai (0.95), Saturia (0.93), Savar (0.88), Manikganj (0.82) and Shibalaya (0.81) UZ. Q Around 70% of accidents occurred at day and 30% at night. Relatively higher number of accidents occurred in between 1000 - 1200 and 1200 - 1400 hours and the January is the unsafe month for traveling along this corridor. Q Minibuses/buses and heavy trucks are involved in 45.6% and 31.6% of accidents, though they comprise 24.9% and 24.7% of total traffic respectively. Q The most predominant accident type is hitting pedestrian which accounts for 56.3% of all known accidents, it is followed by rear-end (12.5%) and head-on (11.9%) collisions. o In the study area overturned type accidents has the highest fatality index of 2.1 followed by head-on (1.54) and hit object (1.42) type of accident. The top most three severe accidents are caused by overturned type accident where 24, 21 and 9 persons were killed. o Within 16 intersections a total 207 (10.8%) number of accidents occurred, rest 1715 (89.2%) number of accidents occurred within the 16 links. o A total 33 locations are isolated as black spots where 58.9% of total accidents and 59.4% of fatal accidents are occurred. Evaluation of Safety Measures o In Balitha site, safety situation improved significantly. The total and fatal accidents are reduced by 69% and 34% respectively. Before-after study of accident pattern shows that head-on, hit object, rear-end collisions are eliminated and hitting pedestrian accidents are reduced by 25%. o In 2nd-Go lara-bridge area, significant reduction of accidents took place after the implementation of improvement works. Fatal and total accidents are reduced by 63% and 67% respectively. Head-on, hit object, overturned and unidentified collisions are eliminated and pedestrian accidents are reduced by 40%. o Before-After analysis of accident data shows that in Golara area though fatal accidents are reduced by 36% but grievous accidents are increased by five times resulting an overall increase of accidents by almost two times. o After implementation of rehabilitation works along the Mirpur-Savar section, total number of accidents and grievous type of accidents are decreased by 10.0% and 20.0% respectively though fatal accidents are unexpectedly increased by 9.6%. Analysis of accident patterns shows that head-on type collision previously which was the most fatal one, is reduced by 60% and unidentified types of accidents are also reduced by 93%. On the other hand rear-end type, side-swipe, hit-pedestrian and over-turn types accidents are increased by nine times, eight times, 170% and 80% respectively. o After implementation of improvement works along Savar-bazar to Aricha-Ghat segment it is revealed that the total and fatal accidents are reduced by 46% and 35% respectively. In terms of accident patterns - over-turn, hitting pedestrian, hit object and head-on type of accidents are drastically reduced by 75%, 36%, 23% and 18% respectively considering 4.25 years of time period after the implementation of the project. o The cost-benefit analysis of three black spots improvement works reveals that the first year accident savings cost in percentage of investment for Balitha, 2nd Golara area and Golara area are 178.6%,251.9% and 9.4% respectively. Finally, based on the research findings of this study, several site specific recommendations are made in order to further improve safety situation along the Dhaka-Aricha highway.