Opinion: Small changes to car access can make a big difference to congestion

This article was published in 2019, in Magazine 145.

Anna Williams (top);
Image as described adjacent
Image as described adjacent

Uh-oh, there’s a traffic jam up ahead,’ says Papa Jim, as his six year-old grandson Leo pushes a little red van to the end of a line of toy cars which snakes up a wooden road and over a two-lane suspension bridge. ‘How are we going to fix it?’ My youngest child and I are watching CBeebies together and this episode of My Story is all about civil engineering. Leo has a think. ‘We could take some cars off?’ His grandad humours him for about five seconds before narrator Nicky Campbell cuts in: ‘That won’t work on real roads!’ The image changes to a view of cars stuck in traffic on a two-lane motorway, followed by free-flowing vehicles on one with three lanes. Before long, Papa Jim is reminiscing about his work dividing the city of Glasgow with a section of urban motorway. Hooray – people can get to work on time!

Or can they? When Papa Jim and Leo visit the site, there is still congestion. Before the Glasgow motorway was built in the 1960s, the American writer Lewis Mumford was already criticising those who tried to cure congestion by building more and wider roads. This quote attributed to him was based on an article he wrote in 1955: ‘Building more roads to prevent congestion is like a fat man loosening his belt to prevent obesity.’

Evidence collected over the subsequent decades has proved this point time after time. ‘Induced demand’ means that car traffic increases to fill the space available. More road space means more cars. The Katy Freeway in Texas has 26 lanes at its widest point but after its completion it was found that travel times had actually increased during peak hours. The only thing that reduces traffic congestion is to reduce traffic. As Leo said: ‘take some cars off.’

In October 2019, members of the UK’s first Citizens’ Assembly on transport agreed with the six-year-old. A representative group from across the Greater Cambridge area was brought together to listen to and question some of the country’s most knowledgeable transport experts. They discussed the evidence and concluded that to reduce congestion, improve air quality and provide better public transport, the Greater Cambridge Partnership (GCP) must reduce the number of cars on the region’s roads. Their top solution was to reallocate road space from cars to cycling, walking and public transport, with over 90% supporting measures to close roads to through traffic. The next two most popular measures for tackling congestion were to implement a flexible congestion charge and to restrict or remove parking.

Presenting their conclusions on the last day of the GCP’s Citizen Assembly, the spokesperson for one of the discussion groups said: ‘We generally accept that we need to become less reliant on the private car, because this expands the space available in the city centre for the people of Cambridge to enjoy.’ In a city where space is limited, switching to more efficient ways of moving people is important. A 3.5m-wide traffic lane can carry 2,000 people per hour by car, 9,000 by bus, 14,000 by cycle and 19,000 on foot.

Cambridge knows this works because it already has the evidence. The Core Traffic scheme (which saw car access to streets like Bridge Street, left, and Emmanuel Street restricted) reduced overall motor traffic in the city by 10%. The number of cycle journeys on Hills Road doubled following the implementation of kerb-protected cycle lanes. Filtered routes like the barrier on Hooper Street between Kingston Street and Sturton Street allow foot and cycle traffic to flow smoothly but eliminate rat-running by drivers. More of these filters could be trialled quickly at low cost. A point closure at the junction of Tenison Road and Great Northern Road would improve traffic flow to the station and one at the Huntingdon Road end of Thornton Road would improve safety for children travelling to school. Lots of small changes could add up to a big reduction in traffic. By maintaining access for cars, but doing more to discourage driving, other forms of transport become more attractive. And suddenly, a nicer place to live and travel is created too.

This piece is based on an article published on 23 October in the Cambridge Independent, which features a monthly column by a member of the Camcycle team.

Anna Williams