Using simulation model as a tool for analyzing bus service reliability and implementing improvement strategies

Area of Science:

• Transportation Engineering
• Operations Research
• Public Transit Management

Background:

• Bus services often suffer from instability and schedule deviations, leading to unpredictable travel times for passengers and operators.
• A significant gap exists in defining and measuring public transportation reliability, with a lack of consensus on indicators and an underemphasis on passenger perspectives.
• Existing reliability metrics often neglect crucial passenger-centric factors like waiting time and on-board crowding.

Purpose of the Study:

• To address the inconsistency in defining and measuring bus service reliability by incorporating both passenger and operator perspectives.
• To develop and evaluate simulation models and control strategies for improving the reliability of high-frequency bus services.
• To identify the most effective strategies for mitigating travel time variation and enhancing the overall dependability of bus transit.

Main Methods:

• A comprehensive literature review was conducted to identify gaps in public transportation reliability research.
• Four key reliability indicators were selected: passenger waiting time, on-board crowding, headway regularity index at stops (HRIS), and bus bunching/big gap percentage.
• A simulation model of bus service was developed and applied to Kuala Lumpur's U32 route to test various control strategies.

Main Results:

• Headway-based dispatching strategies improved headway regularity by approximately 62% and reduced waiting time by 51%.
• Holding strategies at key stops (previous and Prefol) similarly reduced waiting time by 43-44%.
• Integrating headway-based strategies at terminals and key stops yielded the most substantial reduction in passenger waiting time (52.86%) and excess waiting time (81.44%), though crowding levels during peak hours were unaffected.

Conclusions:

• Control strategies, particularly headway-based dispatching and targeted holding strategies, can significantly enhance bus service reliability and reduce passenger waiting times.
• A multi-faceted approach to reliability, incorporating both operator and passenger metrics, is essential for effective public transportation management.
• While strategies effectively reduce waiting times, further research is needed to address on-board crowding during peak periods.