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..

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

Work Journey Rescheduling – Model Development Analysis.

Using Wakefield as a case study, a method was developed of testing the effects on traffic of several different work journey rescheduling strategies. The method consisted essentially of assigning a series of six 0-D matrices to the Wakefield network, each matrix representing the trips for consecutive 15 minute periods over the morning peak. The six matrices were obtained by firstly disaggregating the l 1/2 hr peak matrix by purpose (into home-based work, commercial vehicle, and other trips) and then disaggregating each of these three matrices by time. This temporal disaggregation was based, for the home based work trips, on employee arrival profiles by zone, and for the CV and other trips on cordon crossing profiles. The different strategies were modelled by making adjustments to the parameters of the employee arrival profiles. Other relevant papers in this series are WP 150 Work Journey Rescheduling : Report of Surveys, and WP 168 Work Journey Reschediuling : Results and conclusions

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

Towards The Sustainable City: The Impact Of Transport-Land Use Interactions, Deliverable 6. The Final Report.

Very few transport studies have been able to demonstrate that transport policy measures alone can improve sustainability by reducing fuel consumption and emissions below existing levels. There is therefore an increasing interest in the use of coordinated transport-land use policies, but a lack of understanding of relevant relationships. This research sought to obtain greater insight into these relationships. The main objectives were: (i) to increase our understanding of the impact of accessibility and environmental quality on individuals’ and firms’ location decisions; (ii) to use the findings of (i) to enhance a newly developed strategic transport and land use interaction model; (iii) to use the enhanced model to assess the implications for urban sustainability of the impact of transport policy on location choice; and (iv) to use the enhanced model to assess the relative performance of different combinations of transport and land use strategy. There were two main strands to the work. The first involved the use of a newly developed strategic transport-land use model DELTA/START to test the effects of a range of values for environmental and accessibility coefficients. The tests were based on Edinburgh, and included several combinations of road pricing, fares reductions and light rail, and an alternative land use strategy. The second strand involved a literature review and survey work undertaken in Edinburgh using a stated preference approach to identify values for environmental indicators and accessibility to feed into the model. The survey work of households and businesses was successful in producing values for environmental quality and accessibility. We found that changes in air quality were valued more highly than corresponding changes in noise levels. The survey also revealed some interesting issues that merit further investigation: deteriorations in environmental quality were valued more highly than improvements, there was a greater resistance to increases in council tax beyond current levels than up to current levels and valuations were higher where conditions were worse. The transport strategies were predicted to induce considerable shifts in activity, with city centre populations increasing by up to 20%. However, these substantial changes in activity had relatively small impacts on the transport indicators. The results for the alternative land use scenario showed similar effects. Generally it appears, from the tests involving the strategic transport model that the effects on transport indicators of land use changes, whether induced through transport strategies or imposed through land use planning, are an order of magnitude lower than those of the transport strategies themselves. This is an important policy result since it calls into question how much can be achieved by pursuing coordinated land use and transport strategies

Effects of Bans on Heavy Lorries in London: Impacts on Manufacturing & Service Industries

The report evaluates the extent to which representative samples of manu- facturing and service firms drawn from the inner and outer London areas of South Shoreditch and Brimsdown respectively would be affected by proposed bans on 16 ton and 24 ton GVW commercial vehicles within Greater London. The proportion of commercial vehicle trips to and from South Shoreditch firms affected by the bans would be low and one-quarter of the firms would be affected by a 16 ton GW ban. One in five trips to and from Brimsdown firms is currently made by a vehicle in excess of 16 ton GVW, and two-thirds of the sample of firms would be affected. The majority of affected movements are by suppliers' vehicles rather than firms' own fleets. Three firms particularly likely to be affected were examined in more detail, and the implications of their changing to lighter vehicles investigated. A weight-specific 16 ton GVW ban would impose annual operating cost increases on all firms if they were to maintain existing levels of service with their own vehicle fleets. Under a 24 ton GVW ban two firms would incur cost increases while, for the operations considered, there would be a saving in annual operating costs for the third. The assumption that regulations governing vehicle dimensions and carrying capacity remain unaltered is crucial to the conclusions. Night time 16 ton and 24 ton GVW bans would affect a minority of firms, although the duration of the ban would be important. Weekend bans would not significantly affect the firms

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

Studies of Pedestrian Amenity.

This report, produced for the Transport and Road Research Laboratory, summarises the results of an extensive literature search in two areas of pedestrian research: (I) Estimating the Number of Pedestrian Journeys (2) Pedestrian Amenity The report identifies gaps in current knowledge from the revealed literature and makes recommendations for best practice. Research proposals are made, to help alleviate such revealed gaps, in a companion report

Determination of Priorities for Footway Reconstruction

This report describes a study conducted for Sheffield City Council to obtain pedestriansr reactions to the quality and acceptability of footways of different construction in different conditions, and to assess pedestriansr preferences for different types of footway construction. The results are intended to aid the Council in identifying priorities for the maintenance of existing footways, and preferred surfaces for new or reconstructed footways. The study involved four stages; a new survey to identify footway characteristics of concern to pedestrians; interviews and objective measurements at a total of 13 sites; interviews at a set of eight purpose built trial sites; and analysis and interpretation of the results