Saturday, 6 June 2009

What is going on - part-2

Two people have commented on my previous post about inconsistencies in the cycling statistics.

Both raise interesting points, for which I am grateful. I've been crunching some numbers to try and figure out whether their suggestions could explain the discrepancies. My initial conclusion is that both suggestions are plausible, but the suggestion from Townmouse that cyclists are moving off-road, is less depressing than the suggestion from Shaun that the amount of cycling in the rest of the country is on a different trajectory to cycling in London.

I'll start with the Department for Transport cycling figures. These work out at about 1 billion (1,000 million) cycle trips a year, averaging 2.4 miles each, and totalling 2,400 million miles of cycling each year in the UK.

The DfT estimated a 10% drop in the number of cycle trips in 2007, but their numbers fluctuate quite a bit from year-to-year, and 2006 was an exception. Smoothing the trend over the last 5 years, it works out at about a 0.5% p.a. decline. This is equivalent to 5 million fewer cycle trips on the roads each year.

Then I examined the Sustrans figures. As far as I can make out, about 30% of their network is off-road, but this accounts for about 80% of their traffic. They estimate that there are 354 million trips a year on their total network, of which about half are on bikes (the other half are walkers). Activity on the Sustrans network is rising by about 5% p.a., which would work out at about 8 million additional cycle trips each year.

So the Townmouse scenario would imply that Sustrans have attracted 5 million trips off the roads, onto their traffic-free network, and in addition to this, they have encouraged people to make 3 million extra cycle trips on their network each year. I don't know if that's reality - but it sounds plausible to me. A round of applause, please, for Sustrans.

On Shaun's suggestion that cycling is rising in London and declining elsewhere.

A step change in cycling in London was measured in 2006 (after the bombings). This change alone was equivalent to a 3% increase in cycling across the whole country, and pretty much explains the whole of the increase estimated by DfT from 2005 to 2006. However in London, the increase in cycling activity was sustained for the next year. The figures did not fall back again in 2007. But the DfT national figures did.

Other DfT figures suggest that London accounts for almost a fifth of all UK cycle trips. Assuming the 2006 growth in London has been sustained beyond 2007, then the London Transport cycling figures should now be growing at about 5% growth p.a..

For the DfT figures to be right, and cycling across the whole of the UK to be decreasing by 0.5% p.a. while London increases by 5% p.a. , then simple arithmetic says that cycling activity across the rest of the UK must be decreasing by 2% p.a.

The national strategy is to encourage cycling, and most local authoriites seem to have a goal along the same lines. It is not clear to me whether there is currently a measureable national target for this (the government may have other things on its mind at the moment). But there used to be one that aimed to double the amount of cycling by 2001, and double it again by 2012. This works out at 7% p.a. growth from 2001-2012. In comparison to this, an annual decline of 2% p.a. outside London would be pretty depressing. It wouldn't fit my own impressions of more cyclists on the roads in South-east England. And it wouldn't fit what a lot of councils say they want to achieve.

What I can't find is any recent data for individual councils that would indicate what progress is being made (if any) outside London. So at the moment we are all speculating. It's interesting though.


townmouse said...

There's also the weather - 2007 & 2008 were lousy summers, although a tube strike in London kept the cycling numbers up in 2007.

CTC produced some figures about cycling percentages in various local authority areas and cycle accident rates - I don't know how recent they were, and I could only find the glossy brochure without the underlying data on their site. Karl on Do The Right Thing had some more detailed figures though

Shaun McDonald said...

You might be interested in this post Which is from someone in Edinburgh commenting on the cycling trips in Edinburgh, and the amount of investment that is required.

Basically if the UK wants more people cycling, they need to spend significantly more on cycling infrastructure, like other nations/cities that have high levels of cycling.

As an example, between Friday-Sunday, I cycled 60 miles in Liverpool. The NCN and canal towpath through there had several patches of broken glass, and barriers, that were a struggle to get my bike around. If they were really wanting cyclists, these wouldn't be a problem., hence the need for more investment (or when there is investment, it should be done properly).