Development of a GPS-based driving cycle for intra-city buses in Chattogram City, Bangladesh

Traffic congestion presents ongoing challenges in rapidly growing urban centers like Chattogram, port city of Bangladesh. With limited road infrastructure struggling to accommodate rising vehicular demands, buses serving as the primary mode of public transportation. However, a lack of data characterizing typical bus operational patterns hinders effective strategies to alleviate overcrowding and its economic, environmental, and health impacts. This study aims to develop an updated driving cycle representative of bus operations in Chattogram through onboard data collection and analysis. Speed and location data were continuously logged from two buses traversing four major intra-city routes under naturalistic driving conditions at different times of day. Numerous data were observed to characterize average speeds, acceleration/deceleration rates, time spent idling or cruising, and overall driving modes. Micro-trips were then delineated from the dataset and evaluated against 11 parameters to identify a candidate cycle with less than 5% relative error. Analysis of the velocity profiles revealed route-specific characteristics, with average velocity concentrated 12.37 km/h, acceleration of 0.34 m/s 2 and occasional higher outliers. Comparison with international cycles showed Chattogram's driving cycle exhibited significantly lower average velocities and more moderate rates of acceleration/deceleration, as well as a higher percentage of time spent idling. These findings indicate bus movements face distinctive constraints in Chattogram versus other global contexts. The study develops the first customized driving cycle for Chattogram buses based on empirical speed-time data, accurately portraying prevalent operational dynamics to enable more precise modeling and assessment of fuel consumption as well as tailpipe emissions under existing traffic conditions.