Modelling of the Gap Phenomena at U-turn Provisions on the Median Openings of Inter-Urban Highway Corridors

抄録

In India, most of the capacity augmentation activities have been carried through expansion of the existing bi-directional carriageways into four lane divided carriageways, which has brought the practice to provide the median opening at every 2 km and the same has been brought in the form of an ordinance by the concerned authorities as well. U-turn median openings considered among the most hazardous locations on highways. It is essential to understand the gap phenomena occurring at the median openings. This paper reviewed gap acceptance phenomena occurring at U-turn median openings studied by various researchers in India and abroad. In this study, gap acceptance behaviour on the candidate test sections was evaluated by employing different gap acceptance modeling methods. Based on the results, it was observed that the critical gap of 4.5 seconds is optimum for designing the median opening on inter-urban corridors in India.