Quantifying Travel Time Reliability of Air-Conditioned Public Buses in Urban Area: A Case Study of Kolkata

Public transport plays a major role in transporting people from one place to another for work trips in India. It is a preferred mode for work trips, mainly due to the low travelling cost. Whenever the trip makers travel by public transport mode with higher travelling cost, they expect a more reliable service. If the expectation is not fulfilled, they may like to shift their mode choice from public transport to a service with better travel time reliability, such as para-transit and personal vehicle. This modal shift will affect the traffic flow characteristics of different roadways and also adversely affect the environment. So, this study focuses on estimating the travel time reliability of roadway public transport especially air-conditioned public buses of Kolkata and adopt measures to improve it. As case study, one of the AC buses of Kolkata (Route: AC9) originating from Jadavpur 8B Bus Stand and terminating at Karunamoyee Bus Stand has been selected. The actual travel time has been compared with the scheduled travel time for different times of the weekdays over a week. Moreover, to highlight the difference between peak and off-peak hour, the travel time reliability measures of the AC9 during peak and off-peak hours of the day have been estimated separately as reliability buffer index, on-time performance, travel time measure, and punctuality index. A comparison of different alternative modes on the basis of travelling cost is discussed. Finally, some factors which affect the travel time reliability of buses in Kolkata have been discussed and some measures to improve the present reliability condition of the buses are recommended.