A couple of weeks ago I wrote about how cycling to work became more common in Inner London and less common in Outer London between 1971 and 2001. This provoked an excellent post on the 'cycle of decline' in Outer London from David Arditti (see also here).
Now I'm going to look at what information we have on more recent cycling trends. The results of the 2011 Census won't be out for another year or thereabouts, so instead I'm drawing on the Department for Transport's National Road Traffic Survey data, which you can access here. DfT count the average daily flow of traffic on major roads throughout the country on a yearly basis, and there's more detail on how it works here. I used some of this data for a previous post on trends in cycling at Kings Cross.
DfT's data includes traffic counts at nearly 1,900 count points on major roads in London between 1999 and 2010, with a few gaps here and there. The usual major categories of motor vehicle are counted, as are cyclists. And by averaging all the counts in a particular borough you can get an idea of the trends at borough level, with the caveat that the data doesn't cover minor roads.
The first chart below shows the trend in DfT's average daily count of cycles between 2001 and 2010 in Central London (Westminster and the City of London), the rest of Inner London and Outer London.
So what we see is an increasing divergence between the inner city and the outer suburbs over the last decade. The average cycle count increased by about three-quarters in Central London and doubled in Inner London, but rose by only about a third (122 to 159) in Outer London.
The chart below (click to embiggen) gives some borough-level data, showing the percentage change in average daily cyclists count by borough, with the Inner London boroughs in blue and the Outer London in red.
Update: I have added another chart, this time showing cycling's share of total traffic in each borough in 2001 and 2010. This shows that in the case of some boroughs (like Barnet) which have seen fairly high proportional increases the actual level of cycling (compared to overall traffic) is still quite low.
Again there's a stark contrast between Inner and Outer London boroughs, though cycling increased in nearly every borough over the period. Barnet and Greenwich saw relatively high increases in cycling for Outer London boroughs, while Westminster had a relatively low increase for a central borough (contrast with the City).
My post on Census data included a chart which identified a fairly close relationship between increases in car use and declines in cycling. The chart below plots the percentage point change in cars' share of average traffic flows versus the change in cycling's share, at borough level, and this time the relationship looks even stronger, with areas where cycling increased the most also seeing the biggest falls in car traffic (note, 'car' traffic here doesn't include goods vehicles). Those boroughs in the top left corner (with both big decreases in car traffic and big increases in cycling) are City, Lambeth, Southwark, Islington and Camden. The two Inner London boroughs where the share of car traffic has risen are Newham and Tower Hamlets.
Finally, here are a couple of charts which show the change in the share of cycling and car traffic at each count point, arranged by distance in kilometres from the centre of London (Trafalgar Square, to be exact). There's a good bit of noise at the level of individual count points, but the overall patterns are still fairly clear - the roads closest to Central London generally saw the largest increase in cycling's share of total traffic and the biggest drop in car traffic's share.