What’s on : Cafe-scientifique

Traffic – can we beat the queues?

2 Mar 2022
Start time
7:30 PM
Professor Tony May, Emeritus Professor of Transport Engineering,University of Leeds
Traffic - can we beat the queues?

Event Information

Traffic – can we beat the queues?
Professor Tony May, Emeritus Professor of Transport Engineering, University of Leeds

Last year’s Council survey found that 90% of residents think congestion in York a serious problem. But what can we do about it? As ever in matters related to transport, the answers lie partly in science and engineering, and partly in human behaviour.

I will look at how congestion arises in cities like York, what the predictions are, and why people keep driving in congested conditions. I will argue that congestion is to some extent self-regulating, but represents an inefficient use of the transport system.

I will consider a few of the possible traffic management solutions and show that the way in which the road network as a whole operates is critical. Finally I will discuss the potential of automated vehicles to reduce congestion, and demonstrate that they are likely to have much more wide-ranging consequences.


Tony May has over 50 years’ experience in traffic engineering and transport planning. He worked with the Greater London Council for ten years prior to being appointed Professor of Transport Engineering at the University of Leeds in 1977. While at Leeds he also spent time in consultancy advising on transport strategy for several UK cities. His principal research interests are in urban transport policy, on which he has acted as adviser to the UK government, the World Bank, the International Transport Forum, the European Commission and several national governments. He was elected a Fellow of the Royal Academy of Engineering in 1995, and appointed OBE for services to transport engineering in 2004. He is currently a Trustee of York Civic Trust, and chairs the Trust’s Environment Committee and Transport Advisory Group.”

Slides from this event are available here: YPS 020322 final

Donate to YPS here for Cafe Scientifique

Member’s Report

Prof Tony May has considerable experience in traffic engineering and transport planning, and currently chairs York Civic Trust’s Environment Committee and Transport Advisory Group, advising the City of York Council. Tony described how traffic management theory explains the problems of congestion, and identifies measures to deal with it.

Congestion is widely recognised as a serious problem in York, causing delay, pollution and noise. The cost was estimated to be more than £30 million per annum, and this is predicted to rise significantly. It happens when the capacity of a road does not meet demand, and represents a cost to the driver, mostly in lost time, discouraging road use above a certain, uncomfortably high, level. Hence increasing capacity by more road construction does not help, as traffic increases until the roads are congested again. One possibility is to reduce demand, by promoting development of businesses closer to housing, and encouraging walking and cycling. Another approach involves managing the road network to make roads more efficient. Bus lanes, ‘gating’ schemes limiting the flow of traffic into congested areas, and charges for vehicles using congested areas can help. Streets and neighbourhoods reserved for pedestrians cause vehicular traffic to redistribute – patterns for this can be predicted by well-designed software.

New technology may provide further solutions. York is developing a Smart Transport Evolution Policy (STEP), aimed at allowing traffic signals and vehicles to communicate electronically, to manage the flow of traffic more efficiently. The introduction of autonomous vehicles has been predicted to help with traffic flow, but new research suggests they will lead to an increased use of cars, and may compound the problem.

Margaret Leonard