Analysis of service reliability of public transportation in the Helsinki capital region: The case of bus line 550

Abstract

The rate of automobile ownership in Helsinki Capital Region has been on the rising trajectory, even bypassing population growth rate of the region. The population of the region expected to double in 2050, planning for a sustainable mobility becomes crucial. Effort is being exerted to minimize private car dependence and innovative transport solutions are being tested in the region. Increasing the share of public transport (PT) in the region is the main goal of Helsinki Regional Transport Authority (HSL). To increase the share of PT, improving its efficiency and reliability becomes a crucial strategy by attracting private car users and keeping existing passengers. Therefore, PT agencies need to continuously evaluate the reliability of their service and take improvement actions accordingly.

A reliable PT service is one that adheres to schedule and whose vehicles run on-time. It is generally recognized that deviation from schedule (unreliability) in PT is an important operational problem that affects both operators and passengers. Measuring the level of deviation from schedule helps operators and PT authorities identify and improve gaps in service delivery. Recorded large operational data from Automatic Vehicle Location (AVL) and Automatic Passenger Counter (APC) provide an opportunity to analyze operational performance quality of a PT with a minimum cost.

The objective of the thesis was to analyze service reliability of a circumferential high-frequency bus line 550 in Helsinki Capital Region (HCR) using data from AVL and APC systems. Five different service reliability measures were used in this study. These were on-time performance, headway adherence, vehicle trip-time variability, passenger wait time and passenger travel time. The first three are agency oriented reliability measures and the last two are passenger oriented.

This study has provided a quantitative overview over several service performance measures. The results of the agency-based analysis revealed that for trips along direction 1, 60% of all departures at five stops were on-time using 0.5-minutes-early and 1-minute -late time window. The corresponding average headway deviation was 84 seconds, with average vehicle run time of 1.4 minutes. The passenger-based analysis showed that for all trips along direction 1, the average additional waiting time per passenger was 42 seconds with average additional passenger travel time of 1.7 minutes.

The APC data analysis along direction 1 revealed that average passenger load was 26.5 passengers per bus per direction. The average highest and lowest passenger loads were 38.3 passengers per bus and 2.7 passengers per bus respectively. Overall, Passenger activity over the first half of the route is characterized by high load which is about twice that of the second half of the route.

The overall analysis revealed that performance deteriorated further along the line in both directions. The occurrence of bunching increased towards the end of the route. There is a room for improvement in both agency and passenger oriented measures. Keeping a regular headway on the route is very important, especially for short headway service periods. Passengers perceive reliability mainly in terms of additional waiting and travel time. Improving these aspects of service leads to higher passenger satisfaction which could translate into increased patronage for the PT agency.