Just in case anyone thinks we have made up the point about more road space producing more traffic, this is based on a considerable body of research. In fact the pheneomenun of induced traffic has been recognised since 1925!
For more about this follow the links below.
Road construction have apparently simple aims of providing access to areas previously inaccessible by motor vehicle, reducing traffic volume in one area by moving it to another, or of increasing capacity. Yet each of these aims can result from many, complex motivations. Road construction is prominently promoted as a facilitator of economic growth, however evidence to support a causal relationship between new roads and economic benefit is very contested. There is some evidence that road building induces increases in motor traffic and this is associated with problems of poor air quality, higher carbon emissions, reduced safety, severance for vulnerable road users and congestion. Conversely, there is evidence that new roads which bypass sensitive areas can improve safety and the environment; however, increases in traffic can offset these benefits.
New roads create new traffic
When a new road is built, new traffic will divert onto it. Many people may make new trips they would otherwise not make, and will travel longer distances just because of the presence of the new road. This well-known and long-established effect is known as ‘induced traffic’.
In 2006, consultants Lilli Matson, Ian Taylor, Lynn Sloman and John Elliott examined three major road schemes in detail for an important report for the Countryside Agency and CPRE.
The schemes included the infamous A34 Newbury Bypass which attracted mass protests in 1996. They also examined ten other schemes built since the publication of the 1994 SACTRA report and used data supplied by the Highways Agency’s own Post Opening Project Evaluation (POPE) studies.
· In the case of Newbury, the report showed that traffic levels predicted for 2010 in Newbury were already reached by 2003 – and that traffic had increased by almost 50% in that period.
· New development around the road was partially to blame for the increases.
In the other case studies the report concluded that:
· “Traffic growth on the routes considered was higher than forecast, sometimes quite dramatically so.”