Wednesday 25 April 2012

What we've got to learn from the Netherlands

Update: As commenters below have pointed out, the data may not be comparable enough between the two countries to draw such a strong conclusion, for reasons of definitions and possible different rates of under-reporting. See new post on the topic here.

I used data from the Dutch road safety research institute SWOV yesterday to compare cycle fatality rates in the Netherlands with those in Britain, and Mark pointed out on Twitter that SWOV data also breaks down the number of casualties according to whether or not any motor vehicles were involved. This is handy, as it allows us to see whether the low cycle casualty rate in the Netherlands is due to (a) fewer collisions with motor vehicles or (b) fewer casualties from collisions with pedestrians, other bikes or cyclists just crashing into stuff or (c) all of the above.

This table indicates that 64% of serious or fatal cycle casualties in the Netherlands are the result of collisions with motor vehicles*. This compares with 91% in Britain, from this DfT table**.

We saw yesterday that the cycle fatality rate per km is more than twice as high in Britain as in the Netherlands. According to SWOV data the gap is even larger when you include serious injuries: in Britain there are 556 cyclists killed or seriously injured for every billion kilometres cycled, compared to 96 in the Netherlands (in both cases I'm using the most recent year available, 2009 for the Netherlands and 2010 for Britain).

Put these figures together and you get the chart below, which shows that the rate of serious or fatal cycling casualties not involving motor vehicles is actually reasonably similar in the two countries, 35 per billion km in the Netherlands compared to 49 in Britain. But the gap for collisions with motor vehicles is huge: just over 500 British cyclists are killed or seriously injured in collisions with motor vehicles for every billion km cycled, over eight times the rate in the Netherlands.

I think this shows just about as starkly as possible the consequences of two different approaches to cycling: one which expects cyclists to constantly mix with heavy and/or fast-moving traffic, and one which doesn't. In the Netherlands they very carefully and deliberately try to reduce the chances of a serious collision between motor vehicles and cyclists, and you know what, it looks like it works. In Britain we don't try very hard to do that, and we get the results you see above.

* Select 'Bicycle' under 'Mode of transport' and then nest the 'Type of accident (E-code)' variable in the rows. There are a lot of blanks ('Not matched') under 'Type of accident' for fatalities, so I just calculated the percentage based on the non-blank records)

** Scroll over to 'All areas' and tot up the pedal cyclists killed or seriously injured in collisions with other cycles, pedestrians, or in single vehicle, no pedestrian accidents. The remainder are the results of collisions with motor vehicles.

Tuesday 24 April 2012

No, cycling is not safer in Britain than in the Netherlands

Giving evidence before the Transport Committee today, Ministers Mike Penning and Norman Baker declared that Britain has nothing to learn about cycling safety from the Netherlands because our rate of cycling fatalities per head of population is lower. 

Given that both ministers immediately went on to note that many more people cycle in the Netherlands than in Britain (Mark has the quotes), it is difficult to know what to make of this*. It should be blazingly obvious that if hardly anyone cycles in Country A it is likely to have a lower rate of cyclist fatalities per head of population than Country B where nearly everyone cycles. Any Minister who claims this as evidence that cycling is safer in Britain is misleading either  parliament or themselves. Penning and Baker seem quite proud of their factoid, which implies the latter. That is worrying, and not just for cycling policy.

As many people on Twitter immediately pointed out, a reasonable measure of cycling safety would be to calculate deaths or serious injuries per mile or kilometre cycled. And in fact that's what the statisticians at the Department for Transport do. Their table RAS53001 shows trends in fatality and casualty rates per kilometre for various modes of transport. The fatality rate for cyclists in 2010 was 22 per billion kilometres, down by a third from 33 in 2001 but still some seventeen times higher than the fatality rate for those in cars

So how does this compare to the Netherlands? We are fortunate that the Dutch road safety institute SWOV publishes comprehensive statistics on road safety trends in that country here - and in English too. These figures include fatality rates for the various modes of transport, equivalent to the DfT statistics mentioned above (note, SWOV calls passenger casualties 'Victims per seat'). 

In 2009, the latest year available, the fatality rate for cyclists in the Netherlands was 9 per billion kilometres, less than half that in Britain (21 in 2009). So cycling in the Netherlands, using a sensible measure, is more than twice as safe as in Britain. The evidence of the Ministers to the Transport Committee was wrong (as if that wasn't already obvious).

The SWOV data throws up some other interesting comparisons. The fatality rate for car drivers or passengers in actually lower in Britain than in the Netherlands (in 2009, 1.6 per billion km compared to 2.1). This means that in Britain, fatality rates for those in cars are 13 times higher than for those on bikes, compared to 4.4 times in the Netherlands. The chart below compares fatality rates for cars and bikes in the two countries - again, all based on official statistics.
In summary, we have nothing to teach the Netherlands on cycling safety, and I trust the Transport Committee (and the Times, who will be reporting on the hearing) won't fall for such obvious nonsense from the two Ministers.

* It reminded me of the line in Ulysses to the effect that Ireland had the honour of being the only country to have never persecuted Jews "because she never let them in". 

Monday 23 April 2012

How Energy Performance Certificate data could be really useful, but isn't

One of the frustrating things about discussing housing in this country is that we have historically lacked some key data which would allow us to compare ourselves more accurately with other countries. For example, there are no good statistics on the size of homes we're building now. It is commonly accepted that we build very small homes compared to other new countries, but the only some of the evidence for this is very out of date (see this Policy Exchange report from 2005 which cites these EU statistics from 2002 which cite English House Condition Survey data from 1996). It may well be true that we are building small homes at the moment but we just don't have good enough data to say for sure. [Update: I completely forgot about RIBA's excellent research on this very topic. Thanks to Rebecca for reminding me. So the data gap isn't quite as large I thought, though much of the below still applies.]

Relatedly, we can't really compare our house prices with those in other countries because the simplest consistent comparison, price per square foot or square metre, is not available to us. This matters to people who make housing policy, but it also matters to people thinking of moving house between different countries.

There is a solution in sight, however. The law requires an Energy Performance Certificate to be produced for every house that is sold or rented out. An EPC is drawn up by an expert after looking over the house, and captures key information about the energy efficiency of the house. But it also captures other information, notably the type of house, its size in square metres, and its exact address. There are now about 7 million domestic EPCs, all held on a single register and as of today searchable by address. I just looked up the EPC for a house down the road from me, which is the same kind of Victorian mid-terrace as I share with friends. It pretty much confirms what I thought, which is that our house retains heat about as well as a sieve.

To get back to my point though, what this means is that we've got a huge and growing database of home sizes. And because the Land Registry has recently started releasing its data on house prices, again with the exact address provided, it should be possible to link the two datasets together to calculate the average price per square metre in different parts of the country, for new as well as old houses. More sophisticated analysis could also reveal the extent people are willing to pay for for more energy efficient homes.

I don't know whether anyone in government is working on this. As far as I can see they're not, and that wouldn't surprise me as the key department (Communities and Local Government) is these days shedding statisticians and generally doing less analytical work.

But it should be possible for academics and laypeople to analyse the data in this way. The problem is that the government has decided that EPC data should only be available in bulk to certain organisations and only if they are prepared to stump up the money for it. The costs range from 1p to 10p per record depending on how much detail you want, but in any case this quickly mounts up if you want any kind of comprehensive database at local or regional level.

The government says these prices are to cover the costs of disseminating the data. Maybe that's fair enough and maybe it isn't, but it does mean that the kind of useful analysis I've described above can't be performed by anyone outside central government. So if the CLG are determined to ration access to the EPC data by price I think it should really be doing its own analysis and making the most of this data on our behalf.

Wednesday 11 April 2012

10% of Inner London gets to work by bike

A while back I posted an analysis of Census data showing the trend in the proportion of people who cycle to work in Inner and Outer London from 1971 to 2001. We won't have equivalent figures from the 2011 Census for several months, but we can use another source of information on travel to work, the Labour Force Survey (which I mentioned yesterday when talking about trends in car travel).

The chart below shows the proportion of LFS respondents in Inner and Outer London who reported using bicycles as their main mode of transport to work between 2004 and 2011. One important thing to note is that in each year the data is from the October to December quarter of the survey only, so differences in autumn weather from year to year will affect the results somewhat. Also, as with the car data yesterday these figures are estimates based on relatively small samples of people, and so they have largish confidence intervals around them. This means that there are few if any statistically significant year-to-year changes - but for both Inner and Outer London the trend over the whole period is fairly clear.

In late 2004 around 6% of Inner London workers commuted by bike, rising to around 10% in late 2011. For reference, the share who travelled to work by car fell from 20% to 16% over the same period. A few more years of this and they'll be level pegging.

As we have seen before, cycling is much less common in Outer London, but at least it now seems to be rising, from a 2% share in 2004 to 3.5% in 2011. Not shown is the trend in the rest of the UK, but it's basically flat at around 3% throughout.

[Note: The LFS data here was downloaded from the Economic and Social Data Service]

Monday 9 April 2012

People are using their cars less (but still quite a lot)

There has been much talk here and in other countries about the apparent declines in personal car travel seen in the last few years. Generally these are relatively small declines compared to the huge increases in car travel seen in previous decades, but if per capita car travel has peaked and is falling then that would at least be noteworthy from a social point of view, and possibly quite important for transport policy - see for example this letter from the head of the Transport Planning Society arguing that the Department for Transport's London traffic forecasts are out of whack.

The chart below shows my calculation of daily car travel in miles per person in Britain from 1949 to 2010, derived from these DfT statistics on car travel and population data from the Census and from ONS mid-year estimates.

According to these figures, per capita daily car travel peaked in 2004 at 11.7 miles and has been trending slowly downwards since then. A couple of caveats are probably in order at this point: we are in a recession, which usually reduces travel, and while these figures are per person, strong population growth could in future increase total car travel even if the per capita average continues falling. Finally, the reduction in car traffic is slightly offset by a rise in light van traffic over the same period.

We've also got data for London, though only going back to 1993. The chart below uses population data from ONS but published on the London datastore. The trend here is quite different, already flatlining in 1993 and falling fairly consistently from the turn of the millennium. While car travel per capita has fallen across London, the drop is particularly large in Inner London, down 28% over the period. The average Inner London now travels a shade under four miles a day by car, compared to just over six for Outer Londoners and eleven for the average Briton.

Lastly, much of the talk in the US is about whether car travel is particularly falling among younger people. To try and get a feel for this I looked at data from the Labour Force Survey on the main mode of transport people use for getting to work. Obviously the caveat here is that commuting is only a subset of all travel, but it's the best we can do for now. The chart below shows the proportion of people in broad age groups who reported travelling to work by car in 2004 (the earliest year I could find) and in 2011.

It's really important to emphasise here that this is based on a sample survey, so the estimates have confidence intervals around them (the little black lines). This means that in most cases the change is not statistically significant - including the apparent increase in car use among 16-19 year olds. The only age bands in which there was a clear, statistically significant change over the period were 25-29, 30-34, 35-39 and 50-54 year olds, all of whom were less likely to drive to work in 2011 than in 2004. So there's evidence of a fall in car commuting, but mainly by the 'young-ish' rather than the young (only around half of whom commute by car anyway).