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Date published: 2011/05/13
The Cambridge News says:
Cycling on a key Cambridge road has increased by nearly 10 per cent after controversial wider lanes were painted.
Surveys carried out by independent consultants revealed vehicle traffic decreased by 12.5 per cent and the average speed of what remained dropped by 6 per cent after the Gilbert Road scheme was finished.
The number of cyclists has increased by 9.5 per cent since the £150,000 project was completed in January, the researchers found.
Yesterday Cllr Roy Pegram, its infrastructure chief, said: "These surveys prove that installing high quality cycling infrastructure increases levels of cycling.
"It is also pleasing to see that traffic speeds have reduced on what is an important route for many schoolchildren."
These survey results, which just happen to be what Pegram wanted them to be, are suspicious. Well, the amount of cycling ought to have gone up, although whether by 10% or not is open to question. But the alleged drop of 12.5% in car journeys sounds suspicious.
Before the scheme was implemented there were allegedly around 300k cycle journeys and around 2m car journeys per year. So an alleged 10% increase in cycling equates to an increase of 30k journeys per year. And an alleged 12.5% decrease in driving equates to a decrease of 250k journeys per year. So where are the missing 250k-30k=220k journeys?
Has the local economy been hit so fewer people are moving around? Has the traffic been displaced to other roads? Have some drivers decided to stick two fingers up to Cambridge and take their business elsewhere (given that the city continually sticks two fingers up to drivers)? Well, these might account for some of the alleged decrease. But much more likely, the surveys just happen to suffer from inconsistent sampling and/or poor statistics.
And the alleged drop in average traffic speed is also questionable, and not just because of poor sampling and statistics. So the average speed is not a very useful number. What is more important is how many drivers go significantly above the 30 mph speed limit (although outside of normal hours Gilbert Road is easily safe even at 40 mph).
It is also unfortunate that the mentality of the Cambridge ruling elite happens to be that "cycling = good" and "driving = bad". It leads to perpetually bad transport planning.
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