Highways engineers from as far afield as Australia, Japan and the United States head to York to see traffic management in action at its busiest junctions and in its most congested streets.
It might not seem that way to residents, who often feel they have to battle for their patch of tarmac, but the city leads the world in addressing the problem of how more and more vehicles fit into the same amount of road space.
As the saying goes, a quart will not fit into a pint pot but York transport chiefs have used some lateral thinking to enable them to stretch the pint pot a little at times.
An unusual working relationship with York University academics during the past two decades has harnessed the power of pure mathematics to tackle York's traffic queues and ease the flow of cars around the tourist honeypot.
With its historic buildings and medieval street layout, options for increasing road capacity are limited and Professor Mike Smith said more roads only tended to generate more traffic.
He and his team have produced mathematical models of traffic flow, work-ing from calculations based on the width and length of road and the number of vehicles passing per minute. He said it was "extremely rare" to have such a practical application for pure mathematics.
The next, more complex, challenge is to create soft-ware that "thinks" about the data in a more human way, rather than processing infor-mation within fixed limits.
"From a theoretical mathematical point of view, it's an interesting problem to make best use of existing roads, in an historically-respectful way," said Prof Smith, who is working on similar research for the Department of Transport.
"We're thinking on the edge of what is currently known and an awful lot more research needs to be done. It's an enormous subject...
"York always has had the reputation of being ahead and the council has been sufficiently open-minded to have interaction with me on various things.
"As an academic, it's very easy to spend all your time talking to mathematicians about mathematical niceties which don't see the light of day in another context."
He added: "You don't want long queues but if you widen the road, using the mathem-atical model, the queues can get longer. What we have to do is think of another way of enticing traffic away from the most congested areas, perhaps by widening roads elsewhere.
"When more vehicles are waiting to go than can be accommodated, the excess becomes a queue which has to build until it deters other people from joining it – it's that balance which is critical."
Prof Smith said in mathematical terms, "game theory" applies to traffic research.
"Lots of drivers are comp-eting for a piece of the road – they're all playing a game and everyone is playing their hand as well as they can to get the best outcome for themselves," he said.
"At a higher level, the signal control decision is having an effect on people's behaviour. The question is how to affect that behaviour so that everyone feels better-off – or that you don't upset too many people.
"It's very easy to interfere and make it worse."
Peter Evely, the city's head of network management, said traffic behaves in a way comparable to fluids and so pure mathematics is useful in describing vehicle flows.
The new system spreads the traffic load more widely across the city's road network to ease pressure on the most congested areas, and upgraded technology enables much faster communication between traffic controls.
julie.hemmings@ypn.co.uk