A review of effectiveness of speed reducing devices with focus on developing countries

The heterogeneous traffic conditions in India is making things more complicated in urban areas. Traffic accidents in India are increasing at an alarming rate due to the rapid growth of motor vehicles in the past few years. The number of accidents drop only at sites where speed restriction techniques are implemented for different vehicle categories, especially at locations like approaches to level crossings, negotiation points at sharp curves, approaches towards intersections, accident prone locations, residential streets, streets closures at schools and hospitals etc. In developing countries like India, speed humps and speed bumps are primarily used as speed reducing devices both in urban and rural areas, which is not the case in developed countries where speed bumps are used only on private grounds and speed humps are mainly used on residential roads in urban areas. The effectiveness of speed reducing devices are reviewed in this study to elaborate best practices and recognise gaps in research to set up few scopes for future research in this area. The literature review revealed that most of the speed humps in developing countries have faulty geometrical dimensions when compared to codal provisions leading to problems among road users. Though traditionally speed humps are known to reduce speed and increase safety, they too have disadvantages like, increase in travel time, increase in vehicle operating cost, decrease in capacity of roads and undesirable experience to drivers and passengers. Rumble strips on safety on rural roads on either side of a pedestrian crosswalks is an option to be further explored. Finally, in view of the Indian road conditions, it is observed that Indian guidelines concerning design of speed humps IRC 99-2018 are not compatible with best practice. Therefore, there is an imperial need to frame new guidelines for different type of roads.