House of Commons Select Committee on Transport: Inquiry into Urban Congestion Charging

INTRODUCTION This evidence, submitted to the Select Committee for its inquiry into Urban Congestion Charging, is based on my research into the subject, and professional involvement in studies of methods for managing the demand for urban travel, over the last twenty years. In the 1970s I was responsible, within the Greater London Council, for their studies of the use of comprehensive parking control, physical restriction of road space, and supplementary licensing (a low technology method of congestion charging) as methods of traffic restraint. At the same time, I was an adviser to the World Bank in its study of Singapore's area licensing scheme which is still the only congestion charging system in operation. In the 1980s I was an adviser to the US Transport Research Board in its investigation of appropriate methods for managing urban traffic, and to The MVA Consultancy in its study of electronic road pricing for Hong Kong. Since 1987 I have been involved, as a director of The MVA Consultancy, in a series of integrated transport studies in London (for the London Planning Advisory Committee), Birmingham, Edinburgh, Bristol and Merseyside, each of which has investigated the role of congestion charging as part of a wider transport strategy. I am currently directing a programme of research, funded by the Engineering and Physical Sciences Research Council, which is assessing the relative impact on urban road networks of different methods of imposing congestion charging, on their own and in combination with traffic signal control and bus priorities. This research has used Cambridge and York as case studies. In addition, I am currently acting as one of the technical advisers to the Department of Transport's study of congestion charging in London. (Continues..

Integrated Transport Strategies: A New Initiaitve, or a Return to the 1960’s?

A recurring theme in the debate on urban transport policy in the last few years has been the appropriateness of developing Integrated Transport Strategies as a basis for identifying solutions to current and future urban transport problems. Their proponents, including a growing number of local authorities, see them as a means of ensuring that each element of transport policy complements the others. Those who argue against them, and particularly the Department of Transport, have likened them to the gramd and unattainable, blueprints produced by 1960s land use - transport studies. This paper draws on experience with such studies in London, Birmingham and Edinburgh to assess the strengths and weaknesses of the approach now being adopted, to suggest ways in which it might be further developed, and to identify, in the light of experience to date, those elements of policy which might most effectively contribute to the solution of transport problems

Queue Management Project Model: Strategies for the Management of Queues at Upstream Junctions

This Working Paper is one of a series representing work under a SERC grant on queue management strategies for urban traffic control systems, whose objectives are:- (i)to generalise the strategies developed in an earlier study of queue management; (ii)to develop a computer graphics based representation of queue propagation and management; (iii)to test the strategies' applicability and performance in UK networks; (iv)to investigate their incorporation into standard signal optimisation programs. The study is based on earlier work in Bangkok (May et al, 1988) also funded by SERC, in which queue management measures were developed by trial and error to allow for the fact that queues from downstream junctions frequently blocked upstream junctions and could, as a result, unnecessarily obstruct crossing movements thereby reducing junction capacity and spreading congestion to other areas. The methods developed in that study involved:- (i)predicting the growth and decline of queues from downstream junctions; (ii)estimating the speeds of the starting and stopping waves which determine (i); (iii)identifying the most appropriate stage at the upstream junction in which queues should arrive; (iv)identifying the most appropriate time in that stage during which queues should be present; (v)adjusting the split between stages to allow for loss of throughput in blocked stages; (vi)adjusting the cycle time as necessary in the light of (v). It was steps (iii) and (iv) which involved the greatest element of trial and error, and it was accepted that further work was needed to identify alternative strategies for determining:- (i)during which stage to allow queues to block an upstream junction; (ii)how to adjust the stage timings at that junction to allow for the loss of capacity. This paper reviews these approaches and makes recommendations. It considers first of all, in Section 2, the options at an individual junction. It then considers in Section 3, the application of these options in a range of increasingly complex networks

The Transport Problems of Inner City Firms: An Approach to Solutions.

The paper arises from a recent investigation into the extent to which transport problems affect manufacturing firms and their employees. It summarises the conclusions of that study and notes their implications for the selection and assessment of transport policies designed to assist industry. One of the conclusions is that most problems are local or site- specific; this suggests that local and probably low cost solutions developed by local authorities or by firms themselves may well be more appropriate than programmes of major investment. However, another conclusion is that firms are generally inadequately aware of the effects of their transport problems and the costs to which they give rise; this suggests that the justification even for low cost solutions may not be being made sufficiently apparent to local authorities. These conclusions indicate the need for a more careful assessment of the effects of both high and low cost transport policies on industry. The paper outlines the way in which an analysis of firms' transport problems may be used to develop appropriate solutions and to assess their effects. It discusses some of the problems of such an investigation, using case studies drawn from recent research in Inner London

Area Speed-Flow Relationships by Micro-Simulation: Sensitivity Issues and Problems with the Tracking Approach When Extended to Multi-Zone Networks

This working paper is the third in a series relating to the EPSRC funded project, " The definition of capacity in urban road networks : the role of area speed-flow relationships". The paper looks at the sensitivity of the results to the process of modelling blocking-back in NEMIS, for the same 6x6 grid network described by May and Shepherd (1994b). First of all the blocking-back logic implemented in NEMIS is described. This logic was developed by Shepherd (1990) for use on an arterial network with the intention of blocking cross flows at signalised junctions. When implemented on grid networks with high demands and certain turning ratios this logic can lead to gridlock conditions. The logic implemented in NEMIS caused an irrecoverable gridlock condition i.e. once gridlock occurs it cannot be cleared. Although gridlock conditions may exist for short periods of time in the real world driver behaviour and or external factors combine to relieve the condition eventually. The results will be discussed with and without the blocking-back model implemented in NEMIS for matrix B - heavy inbound traffic. This work also revealed some problems with the tracking approach described by May and Shepherd (1994a) and the definition of demand when extended from single link/zone networks to multi-zone networks. One of the main problems was that of overlapping in the space-time domain, the amount of overlap increasing as demand is increased

Further Studies of the Distributional Effects of Road Pricing

This Working Paper extends the study reported in Working Paper 400, which used the MVA START model for London, disaggregated into three income groups for each of car owners and non car owners, to investigate the distributional effects of road pricing in London. At the time of that study, it was not possible to obtain, from the disaggregate model, output on trips, flows and speeds. The further work reported in this Working Paper has involved extending the evaluation procedures to provide output on trips, flows and speeds; assessing the results from the previous study in tms of these indicators, and testing a fourth charging structure. In all, four charging structures were tested. It is concluded that the additional charging structure tested here, with the original LPAC charging structure, but with charging extended to the off peak in inner London, is by far the most effective in terms of overall benefits, and is similar in its distributional effects to the original LPAC structure

The Impact of Transport Problems on Inner City Firms: A Review.

Previous studies of inner city manufacturing and service firms and studies of industrial relocation are examined to determine the problems of operating in inner areas, the factors causing firms to relocate, and the criteria which determine the choice of new site. These are related to the issues of retaining existing inner area firms and attracting new ones. Much of the previous work is limited in scope, largely qualitative, and frequently at a level of aggregation which makes identification of particular problems or factors difficult. Existing inner city firms perceive the transport problems of their own operations and of their employees as a major disadvantage of their present location, but there is a lack of quantified information on the extent and relative importance of these problems, and whether they are more severe for inner city firms. Transport issues in themselves are not one of the prime reasons causing firms to relocate, although the influence on availability of suitable labour is more significant. At a regional level transport is not one of the most important criteria in the choice of location, but as a determinant of site at the local level it is mentioned frequently enough to warrant further study. A number of other factors involved in these decisions are to a greater or lesser extent related to transport. To place firms' transport operations in a wider context transport costs, industrial traffic generation, and the effect of some forms of control are discussed

Control of Congestion at Highly Saturated Signalised Intersections: Experiments on Rama 4 Road, Bangkok

INTRODUCTION This working paper is the third in a series of three on the control of congestion at highly saturated signalised intersections. The other papers in the series are: WP 220 Control of Congestion at Highly Saturated Signalised Intersections: 1 - Survey Methods WP 221 Control of Congestion at Highly Saturated Signalised Intersections: 2 - Experiments at an Isolated Junction. After a brief explanation of the purpose of the study, and the part played by the Rama 4 experiments, this paper describes how the input data for the experiments was collected, updated and prepared for use in standard signal setting programs. The conduct of the actual experiment is then described followed by results and conclusions thereof

Development of a Cycling Policy for York Technical Report

In early 1983 York City Council and North Yorkshire County Council commissioned the Institute for Transport Studies to carry out a study of cycling in York. The terms of reference were to: Include an origin and destination survey of current movements by trip purpose and an assessment of future demand, indicating the likely mode from which any transfer will occur; Identify problem areas following discussions with various cycling groups and a study of accident statistics; Take into consideration any previous decisions of the City Council for investigation; Assess the appropriateness of the recommended standards for cycle facilities to a compact urban area; Propose various solutions to problems where appropriate, assess the effect on other road users, and formulate a basic cycling plan for York. Propose various solutions to problems where appropriate, assess the effect on other road users, and formulate a basic cycling plan for York. The Institute for Transport Studies at the Univeristy of Leeds was appointed to carry out the study with Professor A.D. May as the Director of the Study and Mr. D.A. Waring as Research Engineer. Work commenced on this project in June 1983 and was completd in May 1984. The recommendations arising from the study are contained in a separate Summary Report, available from the Institute as Working Paper 175

Work Journey Rescheduling: Results and Conclusions.

An assessment was made of the effects of changes in working hours on traffic conditions in the city centre of Wakefield. The study used survey data arid modelling techniques which are described fully elsewhere, and summarised in section 2 of this report. This report concentrates on the results of the study and the conclusions to be drawn from them. Assessments were made of traffic conditions had the current level of flexible and staggered hours operation not been introduced, and as the result of four different levels of increased rescheduling of work journeys. In all cases, results were presented in terms of changes in the temporal distribution of trip ends, cordon flows, and the network parameters of vehicle hours, vehicle kilometres, average speed and vehicle delay. In the peak 15 minutes car driver trip ends would have been 15% higher without current work hour arrangements, and 11% lower with further rescheduling. Changes in car driver trips entering the central area would have been about half as great as these changes in trip ends. Because the network is not operating at capacity, these changes would have had little effect on network performance generally, but time spent in queues, and delays on two congested approaches would have changed in the peak 15 minutes by + 20%. The report discusses the reasons for these relatively small changes and suggests criteria for identifying those cities in which work journey rescheduling could more successfully reduce congestion. It also recommends potential improvements in the analytical process adopted