New roads discourage cycling & cars soon get jammed, finds study

Carlton Reid
New roads discourage cycling & cars soon get jammed, finds study

A new report has found scant evidence that building more roads produces economic benefits. In fact, they soon lead to even more traffic jams, damage the countryside and discourage other ways of getting about, such as walking and cycling.

The End of the Road report has been produced for the Campaign to Protect Rural England by travel consultantants Transport for Quality of Life, and challenges the government claim that the "economic gains from road investment are beyond doubt." 

Highways England is soon to start consulting on which road schemes will receive funding, set to triple to £3 billion a year by 2020.

The CPRE report shows how road building over the past two decades has repeatedly failed to live up claims of reducing congestion. In fact, multiple studies over many years have demonstrated that building roads leads to more traffic in a spiral known as "induced demand."

Transport academics tend to credit the discovery of induced demand in transport to J.J. Leeming, a British road-traffic engineer and county surveyor, writing in 1969. He observed that the more roads are built, the more traffic there is to fill these roads. The idea was conceived shortly after German mathematician Dietrich Braess released the Braess’s paradox which shows that “selfish” motorists can’t be relied upon to consider the optimal travel times for all rather than just themselves, leading to delays for all.

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But induced demand was known about long before 1969. Writing in 1866, surveyor and engineer William J. Haywood, one of the builders of the Holborn Viaduct, said the new thoroughfare would attract more travellers: the “facility of locomotion stimulates traffic of itself”.

The CPRE's new report examines 80 road schemes from by Highways England, especially the A34 Newbury Bypass, M65 Blackburn Southern Bypass, A46 Newark – Lincoln dual carriageway, and the A120 Stansted to Braintree dual carriageway.

Traffic was found to increase much more in road corridors with new schemes than background traffic in the surrounding area. Schemes completed eight to 20 years ago demonstrated a traffic increase of 47 percent.

CPRE's head of infrastructure and legal Ralph Smyth said:

“The Government is keen to sell the biggest road-building programme since the 1970s, but this is a programme that will forever fail on its own terms, producing a depressing, self-perpetuating cycle of more and more roads that do little for the economy and harm the countryside."

The End of the Road report stresses that building new roads undermines efforts to encourage modal shift, such as more people walking, cycling and taking public transport.

"If road schemes generate additional traffic, a proportion of this must be replacing trips that would otherwise have been made by public transport, cycling or walking," says the report adding that this will lead to decreased physical activity and therefore more costs for the NHS.

As an alternative to the self-defeating building of more roads, which locks in unhealthy car-dependency, the report suggests that housing and employment should be focussed in towns and around existing and new rail stations, "designed to densities and of an urban form which make walking and cycling the modes of travel of choice."

It also suggest more investment in rail and light-rail networks, linking in with walking and cycling.

The lead author of the CPRE's report is Lynn Sloman, former Assistant Director of the environmental pressure group Transport 2000 fand author of "Car Sick" of 2006.

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