Operational effects of speed breakers: a case study in India

Abstract

Traffic condition in India is highly heterogeneous consisting of vehicles of different static and dynamic characteristics. The speeds of all vehicles are non-uniform. Therefore, to regulate the speeds of different category of vehicles while travelling on a sharp turn or while approaching towards an intersection or buildings like schools and hospitals, traffic calming devices are provided on the roads. Speed breakers are one of the most commonly used traffic calming devices in developing countries like India. Geometry of the speed breakers are based on IRC 99 which says that the width of speed breakers should be 3.7 m and the height should be 0.1 m for urban roads. The codal provisions also suggest that the vehicles should be able to cross the speed breaker at an advisory speed of 20 kmph. However, it is observed that most of the speed breakers have faulty geometrical dimensions owing to various problems to the road users. The width of the speed breakers are usually observed to be narrowed down which increases the chance of road crashes due to sudden braking of vehicles encountering it. Further, it also leads to sudden slowing down of the whole traffic stream leading to traffic congestion. It also reduces fuel efficiency of the vehicles leading to overall increase in vehicle operating and maintenance costs. The present study reviews in detail the provisions provided in the IRC code for construction of speed breakers. Thereafter, a practical on field study is conducted to examine the dimensions of various speed breakers across various cities in India, and compare their dimensions with the provisions provided in the IRC code. Further, the operating speed of the vehicles while crossing the speed breaker is also noted down and compared with the suggested speed as provided in the code. Finally, a detailed comparison between speed reduction at the speed breaker and their dimensions has been analyzed. Speed reduction of different category of vehicles has also been examined in detail.