Project: Model To Assess Public Transport Reliability

Reference: STP 14/6/43

Last update: 19/12/2007 09:44:33

Objectives

To develop algorithms to represent bus schedules, timetables and controls within a netwok microsimulation framework;
To directly model passenger flow and routes through a network with inputs from a public transport assignment model;
To develop reliability indicators from the standpoint of service operators, passengers and network managers, and to quatify the causes of unreliability such as those due to variability in traffic congestion and passenger demand;
To construct a well-integrated micro-simulation model of the Warrington road and public transport network, to use this model to evaluate a range of strategies and options, and to estimate their economic efficiency and service reliability.

From the results of this research, guidance could be developed and disseminated to the transport community. In addition a modelling tool will have been developed which could be used to assess the effects of public transport priority measures and advanced bus operations on service reliability.

Description

Research within the FIT Programme will address the challenge of 'A New Deal for Transport' by encouraging research that is responsive, collaborative, multi-disciplinary and multi-modal leading to technological development and innovative solutions for problems experienced in the transport sector.

To develop methods which allow a realistic representation of bus operations and a direct assessment and analysis of public transport reliability.

Contractor(s)

Leeds University
Univ of Leeds, Leeds, LS2 9JT

Contract details

Cost to the Department: £94,369.00

Actual start date: 09 June 2003

Actual completion date: 31 December 2005

Publication(s)

DRACULA Case Study: Warrington Public Transport Priority Measures
Author: D Bayfield
Publication date: 01/01/2004
Source: Institute for Transport Studies, University of Leeds

The cost of travel time variability in bus infrastructure facilities
Author: Y Hollander
Publication date: 01/01/2005
Source: Institute for Transport Studies, University of Leeds

A comprehensive review and analysis of public transport reliability measures
Author: Liu, R., Woodham, C.A.. and Sinha, S
Publication date: 01/01/2004
Source: ITS Leeds

Modelling Public Transport Reliability: a Case Study of York
Author: S Sinha
Publication date: 01/01/2004
Source: Institute for Transport Studies, University of Leeds

Summary of results

  1. All four primary objectives have been completed in developing a more detailed passenger model which allows a much wider range of travel behaviour to be modelled. It is, however, worth mentioning that it became apparent at an early stage of the project that this was a much larger task than at first envisaged, given the importance of monitoring bus reliability the local authorities and bus operators are now obliged to undertake. A summary of the achievements relative to the four objectives are given below.

    - To develop algorithms to represent bus schedules, timetables and controls within a network micro-simulation framework;

    - To directly model passenger flow and routes through a network with inputs from a public transport assignment model.

    The primary aim of the project was the development of improved micro-simulation procedures capable of:

    (i) assigning passengers to routes enabling passenger flow through a network to be modelled, and

    (ii) realistically representing bus operations in a congested urban network, allowing delays to be assessed.

    This has been achieved by the development of new algorithms of passengers and bus operations, and the implementation of the algorithms in an existing network model, DRACULA, to form an integrated highway and public transport network model. The integrated model allows the interplay of the passenger demand, bus operation and network congestion to be properly assessed. Software was developed to link an existing public transport assignment model (PT-SATURN) with the new integrated model.

    - To develop reliability indicators from the standpoint of service operators, passengers and network managers, and to quantify the causes of bus unreliability such as those due to variability in traffic congestion and passenger demand;

    This has been achieved by a combination of a comprehensive literature review and extensive discussion with the bus industry partners in the project - undertaken as Task 1, together with the development of data collection procedures from the above integrated model. A small-scale case study along a bus route in York was carried out to quantify the causes of unreliability; the study highlighted some real issues in the design of bus priority measures along the route, then suggested and evaluated a number of viable solutions.

    - To construct a well-integrated micro-simulation model of the Warrington road and public transport network, to use this model to evaluate a range of strategies and options, and to estimate their economic efficiency and service reliability.

    A base-year SATURN highway traffic network model of Warrington was extensively updated and details added. Combined with the results from PT-SATURN public transport assignment results, an integrated model of road and public transport network for Warrington was developed. The full model was verified through visual inspection of the simulation which was considered to be satisfactory by the local authority and its main traffic modelling contractor. The model was then used to test the base-year scenario and one scenario with bus lane schemes; measures of bus reliability in terms of journey time variability and passenger excess wait time were estimated. The results confirmed those found in the small case study in York, but also highlighted issues with the design of the bus lanes. Further calibration of the model and investigation of the test results were needed, but the "proof-of-concept" was there and the base traffic model was available for the local authority to use in practice.