Map of 2001-2011 population change in London

Update: Those intelligent people in the Intelligence team at the Greater London Authority have now made a better map of population change between 2001 and 2011, which I think you should look at rather than mine (there's more GLA analysis of the Census here). 

The GLA map is better because (a) it uses ward boundaries, which unlike the statistical boundaries I used have not changed over time and therefore offer a like-for-like comparison; (b) it compares Census 2011 population to the 2001 mid-year population, which the GLA thinks is a more reliable figure than the 2001 Census figure, and (c) it's interactive! So I've put my map below the fold here, just for reference.

The gender dimension of road danger

This BBC article about 'black box' devices in cars which monitor your driving for insurance purposes features lots of standard-issue outrage from drivers who can't see why how badly they drive should be anyone else's business but it also touches on the interesting issue of whether female drivers are safer than males. You don't have to look too hard to find plenty of commentary on this topic, but hard facts are more difficult to come by. Here's something from 2004:

Male motorists were responsible for 88% of all driving offences that resulted in findings of guilt in court in England and Wales in 2002, the Home Office statistics showed. Furthermore, men committed almost all the most serious offences, such as causing death and dangerous driving: women committed just 6% of the death or bodily harm offences in 2002 and just 3% of dangerous driving offences. Men were also responsible for 96% of vehicle thefts and 97% of offences relating to motorcycles.

Those are pretty huge differences, but perhaps, and I'm just speculating here, partly down to different treatment of men and women by the justice system. You can also look at the different rates at which men and women are involved in collisions resulting in injury, with the caveat that the figures don't necessarily imply anything about who's at fault. I looked at DfT's 2011 road casualties data, and found that in 85% of collision where a pedestrian died the driver of the vehicle (mostly cars but also vans, motorbikes, HGVs and a couple of bikes) was male, compared to 71% of cases resulting in serious pedestrian injury and 69% of cases resulting in slight injuries. This table suggests that men account for about 65% of the miles driven in Britain, so they do seem to have a higher rate of involvement in pedestrian casualties (trying to calculate rates for all kinds of collisions is more complicated).

What was most interesting to me is that males also account for a higher share of pedestrian casualties too: 68% of fatalities, 60% of fatal or serious injuries and 57% of slight injuries in 2011, according to this table. Other figures show that men and women do roughly equal amounts of walking, so these numbers do seem to provide some support for the idea that guys take more risks - or maybe just have worse judgement - than girls whether they're in cars or on foot.

The wider issue is that men also have more influence over transport policy and road safety, with the result that the issue is treated more as one of personal responsibility than as one of public health. The same cognitive biases that tell us we should be able to look out for ourselves ensure that we basically can't.

Urban expansion: learning from 19th century London

Paul Collier says that African cities should learn from the example of 19th century London when it comes to housing policy. London was able to build decent housing for working people because its building regulations weren't onerously high, because landowners split their land up into separate plots for small firms to build out while retaining ownership themselves, and because the legal system of ownership and tenure was clear enough to allow building societies to lend with confidence.

All good points, but I would just a couple of things. First, 19th century London also benefitted from rapidly falling transport costs, which enabled development to take place on greenfield land. Stagnation in transport technology makes it harder to keep expanding the urban frontier and compels us to try and redevelop existing urban areas.

Also, it's not just African cities but 21st century English cities which could learn from the example of Victorian London, in particular on the land ownership front. What usually happens these days is that a developer buys a large site and then waits for the most opportune moment to develop the whole thing, which can take a long time. This arrangement means you are basically creating a local land monopolist, with all the problems that entails. Ideally, government should instead try to split the task of building the site out between a number of smaller firms, who would then be competing against each other, which should raise both the timeliness and the quality of development. Obviously this is much harder when government doesn't own the land, although the German practice of umlegung (land assembly) seems to be a reasonably close approximation.

If you like your neighbourhood so much then let more people live there

Matt Yglesias has an excellent post here about the lovely city of Santa Monica, which prides itself on its greenness yet has seen barely any population growth in recent decades despite sky-high house prices.

For Santa Monica you can subsitute any number of nice, exclusive places in the US and across Europe. Here in London we have an excellent example in the Royal Borough of Kensington and Chelsea, where the average house price is over a million pounds (pdf) but where the population and the number of households actually fell, albeit only slightly, between the 2001 and 2011 censuses compared to an increase of 8.3% across London as a whole (xls).

Demand for housing in K&C is clearly through the roof, so how come its population isn't growing? The reason is that planning policy, backed up with overwhelming political support from borough residents, makes it very difficult to build any new housing in the area. So very little does get built, so rising demand just pushes up prices.

K&C is a somewhat extreme example (70% of it is in a conservation area!) but the general pattern is widespread. More people want to move to urban areas to be closer to job opportunities or to avail of improvign urban environments, but the people who are already there don't want their neighbourhood to change so they campaign against new housing developments, and politicians dutifully vote those developments down. The supply shortfall pushes up prices, so only the richest can afford to move in and those less well-off either stay put or move to somewhere less nice and/or further out.

I think this is quite a bad situation, because it results in affordability problems, greater segregation by income and environmentally damaging urban sprawl as housing supply is diverted to places further away from jobs and services. And indeed, you hear a lot of concern about these issues in urban political discourse - but what you generally don't hear is any connection being made with all those anti-development crusades that contribute so much to the problems.

Of course there may be downsides to densification of existing urban neighbourhoods in response to rising demand. A lovely neighbourhood may not look quite as lovely when it's had some buildings replaced or some blocks of flats added. Personally I think these things can go either way and some areas would be much improved by densification, but I also think these basically aesthetic considerations are just not that important compared to the effect on people's lives of making more housing available in places where they want to live.

At its root, this is an issue of social justice and of personal ethics. People who care about social justice should be worried about a political process which gives all the power to people who already inhabit a neighbourhood and none to the people who would like to (see Matt Yglesias again). And people who think of themselves as ethical should ask themselves whether they can justify excluding others from enjoying the same neighbourhood they like so much, while adding to our already serious problems of affordability and car-dependent development.

A land value tax would be unpopular for the same reasons that it would be great

I was surprised a while back to find that the Liberal Democrat conference policy paper on housing included a call for a land value tax (LVT), because the current party leadership shows absolutely no interest in implementing one. But then LVT has long been a cause beloved of earnest policy wonks and loathed by politicos. I'll get to why that is in a moment, but first it's worth rehearsing what I like to call the neoliberal-environmentalist-progressive case for an LVT.

An LVT is a tax on the value of land, excluding the value of anything built on it. The logic is that the relative value of different plots of land is nothing to do with the landowner's activities but is purely a product of their locations and the access they grant to amenities, infrastructure and other 'locational goods'. And because land is fixed in supply and location, taxing it doesn't have the distortionary effects that taxing income or consumption might. So because the community effectively creates the value of land, the community should also draw the benefit rather than let landlords get rich by doing nothing.

Part of the attraction - for policy wonks - of an LVT is that it would provide an incentive for valuable land to be used for its most productive purpose. So if you own a plot of land in a great location, the high tax on it gives you a very strong incentive to get as much money out of that site as possible, which might mean building offices or housing or whatever - the point is that you do with that land whatever maximises its value, subject to whatever constraints the planning system sets . This outcome is good for the landowner (who reduces their net tax bill), good for the government (who gets the tax revenues) and good for whoever ends up occupying the buildings on the land, as they get homes or workplaces they would otherwise not have.

But as Duncan Stott Stoddard points out on the IEA blog, there is a significant problem here, in that current planning policy in this country (and most others) is mainly concerned with restricting landowners' abilities to maximise income from their land by building stuff on it. Building something a bit taller than the surrounding buildings is basically illegal across large swathes of this country, as is switching uses from residential to commercial or whatever. Retaining these extremely strict regulations on land use would negate much of the benefit of an LVT. In fact, it would arguably make an LVT quite unjust, in that you would be increasing some people's tax bills while preventing them increasing the income from their land to compensate.

So as Duncan says, an LVT should really go hand in hand with looser planning regulations. That way you maximise both the benefits of an LVT and the benefits of looser planning - the latter because if you loosen up planning policy without an LVT you are basically enriching landowners (by increasing their potential income) again without them having done anything to deserve it. And allowing landowners with valuable land to build lots of housing on it also means that if they pass the cost of their LVT onto those who occupy the land (i.e. tenants or apartment owners), then obviously the more occupiers there are the lower the cost is for each of them. This can mean that the per-household LVT is significantly lower in city centres than it is in the suburbs - which is also a benefit, since people living at higher densities are imposing fewer costs on the community in terms of infrastructure requirements, energy use and so on.

So a combination of a land value tax and looser planning regulations would very likely deliver cheaper housing, more tax revenues, a fairer distribution of wealth, a shift in the tax system away from distortionary income taxes, and a more sustainable and energy-efficient pattern of land use. Who wouldn't want that?

Lots of people, it turns out. In particular you've got all those homeowners who bought into a neighbourhood which then improves around them, driving up the value of their property and generally making them very happy with their lot. Coming along and telling them that actually they should pay a bit more for their good fortune and perhaps consider building a block of flats on their land will probably have this large and vocal constituency reaching for the pitchforks. But as well as the people who have got lucky in the property market, an LVT will probably also incite the ire of anyone who aspires to get lucky in the property market, which is to say pretty much everyone.

After all, just about everyone everyone wants to be that person who buys a property and sees it rocket in value through no skill or effort of their own. Yes it's unearned wealth and so policy wonks will say it raises important issues of social justice and economic efficiency and yadda yada, but everyone wants to achieve huge wealth, preferably without earning it. An LVT says nobody should get away with amassing unearned wealth through locational good fortune without paying some appropriate fee to providence.  In other words, it is an attempt to put a stop to free lunches via the property market. But people like free lunches, and if they don't currently have access to one they like to think that some day they will. And that, it seems to me, is why politicians are scared of land value taxation.

Neverthless, I do think the world would be a better place if we had more land value taxation, and it could happen if enough people get behind it and crank up the machinery of persuasion. Environmentalists, progressives, tall-building aficionados and tax reformers should recognise the benefits, hold their noses and start forming coalitions to lobby for this, because our leaders are going to require a lot of persuading.

We choose how congested our roads are

This BBC article about traffic congestion in Sao Paulo carries on like 180km traffic jams are an inescapable fact of life there and congestion is an insoluble problem. They even find a professor of engineering and transport from a Sao Paulo uni to say that "No city in the world will ever manage to end congestion".

Completely ending traffic congestion may be very difficult, but there are certainly cities who have reduced it substantially by doing things which Sao Paulo has chosen not to do. Congestion charging in Stockholm, Singapore and London has sharply reduced the level of traffic in their inner cities, and there is no doubt that if they were to whack up the prices that traffic would fall even further. Many cities have also built comprehensive, high quality rail systems, and given buses priority express lanes on main roads. But in Sao Paulo, instead of a congestion charge they introduced a rotating car number-plate ban which reduced traffic in the short term but mainly encouraged people to buy more cars. The metro system is far too small given the size of the city. And historically their buses haven't been given enough priority over other traffic and so suffer from the same congestion as cars. Hence, huge traffic jams.

I'm not suggesting these are easy choices, especially for a rapidly expanding city like Sao Paulo. Most cities are not fortunate enough to have built a huge underground system over a hundred years ago when it was nice and cheap, like London did. Sao Paulo now has a growing bus rapid transit system and big plans to expand the metro, but because Brazil is a democratic country where most people have the right not to be turfed off their land, building vast infrastructure projects is much harder and slower than it is in, say, China. Likewise, it's not easy to find the money to build a subway network big enough to adequately serve a city of 20 million people, or to convince drivers that they should pay to use roads they previously used for free. Those kinds of things are very hard, which is probably why more cities don't choose to do them.

But one reason they're hard is that many people are not convinced they are worthwhile, and that in turn is partly because the public discourse around these issues seems wilfully uninformed. There are solutions available which are workable and demonstrably effective. It's one thing to consider and reject them, but to pretend they don't exist is something else altogether.

Mapping pedestrian casualties in London

The Department for Transport publish full data on recorded road casualties on data.gov.uk, and I've been playing around with the data a bit recently, partly as a way of learning some new software skills.

The map below (best viewed at full size) is one result, and shows serious and fatal pedestrian casualties in London in 2011 which were the result of collisions with bikes (in red) or cars (in turqouise). Bigger circles represent fatalities and smaller ones serious injuries.

In total there were 980 serious or fatal pedestrian casualties in London in 2011, of which 33 resulted from collisions with bikes (one fatal) and 609 resulted from collisions with cars (38 fatal). The remainder resulted from collisions with motorbikes, goods vehicles, buses and other vehicles, but I didn't show them as I wanted to keep it simple and was mainly interested in comparing cars and bikes.

Techie details: I downloaded the csv data for casualties, accidents and vehicle records for 2011, used R to merge and filter the data, used QGIS to convert the data to a shapefile, and used Tilemill to combine that shapefile with some other layers, apply stylings and export to PNG. Tilemill does some puzzling things like leaving some of the markers brigher than others for no apparent reason, but hopefully that will be ironed out in future versions.

Problems with comments

Apparently some comments are not appearing on the site, even though I can see them in the Blogger admin system. This seems to be a problem with Disqus not picking up comments made via the mobile version of the site. I'm trying to fix it at the moment. I think this only affects one comment so far, and it hasn't been lost.

Also, some readers have said they can't leave anonymous comments on the site. You should be able to - just post as a 'Guest' and enter a made-up email address.

Reviewing TfL's road safety plan, Part 2: Which target?

This is the second post looking at Transport for London's draft road safety plan, which is out for consultation here until the 28 September. Whether you agree with the draft plan or not I encourage you to respond to the consultation: 2,805 people were recorded as killed or seriously injured on London's roads in 2011 alone, so this stuff matters.

In the first post I reviewed TfL's take on recent casualty trends in London, noting that the target to halve the number of cyclists killed or seriously injured ('KSI', in the jargon) on London's roads was missed, with the number of KSI falling by just18% compared to a 57% drop in overall casualties (see chart below from the last annual report).

TfL argued that this failure was due to the enormous growth in cycling over the same period. Which is largely true - but then why not set a target to reduce the rate of cycling casualties per trip or per kilometre cycled? As I mentioned earlier this month, TfL have recently calculated casualty rates per 100 million kilometres travelled by different modes in London, and the Department for Transport also do a similar calculation by region, so the information is available to monitor such a target. And according to the Road Danger Reduction Forum, TfL have said in the past that they intended to adopt rate-based casualty reduction targets to deal with this problem of absolute casualty targets being affected by changes in trip rates. Finally, the government's new road safety framework proposes rate-based casualty reduction targets at the national and local level (see p.72 here).

These are all good reasons to adopt a target to reduce the rate of cycling casualties per distance travelled, and similar targets for other modes. But TfL have decided against such a target; in fact they have decided against having any target of any kind to reduce cycling casualties. Instead, they propose a target to reduce the absolute number of all KSI road casualties by 40% by 2020 from the base period of 2005-09.

TfL describe this proposed target as 'challenging' (p. 26 of the plan), but when you look at their own chart it doesn't really seem all that challenging.

The number of serious or fatal road casualties in London fell by more than half in the nine years between 2001 and 2010, and reached a low of 2,805 in 2011. TfL are proposing to reduce it to 2,176 by 2020, which would be a reduction of 22% over the next nine years, comparatively a much slower rate of reduction.

So this proposed target sounds distinctly unchallenging, even if you assume, as I think TfL must be doing, that traffic starts growing strongly again during the period. Another partial explanation is offered on the same page, when TfL say that this target "is based on the assumption that the existing road safety programme continues, but does not include the effects of any new measures". In other words, TfL aren't including the effect of any improvements from the junction review or any attempts to 'Go Dutch' in terms of cycling infrastructure. Whether that is because they don't know what to expect from these policies, or know not to expect very much, is not made clear.

All this stuff about targets might seem like fairly irrelevant bureaucracy to some, but I think it does matter, because genuinely challenging targets with a high political priority attached do in practice lead to the re-allocation of resources, and because they can help to focus minds and change cultures within bureaucracies. TfL have recently given hints that they are genuinely changing their policies and practices to reflect a new focus on reducing road danger, but this draft road safety plan and the main target proposed don't seem to reflect any of that. I think if cycling is to get significantly safer in London then we need to focus TfL's minds on reducing the casualty rate, and the road safety plan is a good place to start with that. If you agree, write to them and say so before the 28th.

Reviewing TfL's draft road safety plan

Transport for London are currently consulting on a draft new Road Safety Plan for London which sets out proposed targets and policies for the period up to 2020. The consultation period closes on 28 September and I strongly encourage everyone to respond - there is a questionnaire you can fill out to make it a bit easier.

I plan to do a few posts analysing the draft plan in detail, as it's quite an important document. This first post looks at how TfL describe recent trends in road safety in London; the next one will probably focus on the target they propose to adopt, and the last will look at some of the policies they do and don't propose to implement.

The number of road casualties, including the number involving fatal or serious injuries (crudely abbreviated in the jargon to 'KSI' for 'killed or seriously injured'), has fallen substantially in London over the last couple of decades, and TfL are rightly keen to highlight this. The headline figure is that the number of KSI casualties in 2010 was 57% lower than the average figure for 1994-98, which has been used as the baseline until now. This means that the overall target in the original London Road Safety Plan (first published in 2001 and then updated with tougher targets in 2005), for a 50% reduction in KSI casualties by 2010, was met.

But that first Road Safety Plan didn't just set an overall target for road casualty reduction. There were targets for individual modes too, to try and ensure that casualties were reduced across the board. Following the 2005 review, these mode-specific targets were:

• A 50 per cent reduction in the number of cyclists and pedestrians killed or seriously injured 
• A 40 per cent reduction in the number of powered two-wheeler users killed or seriously injured

There was also a specific target to reduce the number of children killed or seriously injured by 60%.

The targets for KSI casualty reductions among cyclists and motorcyclists were not met. As the chart below (from the last annual monitoring report) shows, the number of cyclist KSI casualties fell by only 18% and the number of motorcyclist KSI casualties by 34%.

Strictly speaking, then, the original road safety strategy failed to meet its targets. TfL, however, argue that the failure to hit the targets for cyclists and motorcyclists was due to large increases in both cycling and motorcycling in London, and that the underlying casualty rate for both modes actually decreased.

I don't know much about motorcycling trends but over the longer term it is certainly true that the cycling casualty rate has fallen in London - see, for example, the chart below produced by Fullfact.org from TfL data.

There are a few things you could say in response to this argument. The most obvious is that they can't have it both ways - TfL's target was to reduce the absolute number of cycle and motorcycle casualties, and if you go back to the 2001 road safety plan you can see that this target was set in the knowledge that use of both modes was rising. Secondly, if they now think that the rate of casualties per trip or per mile travelled is more important, then why not make that the target, or better yet set a target to reduce both the rate and the number of casualties? Thirdly, it is clear from the chart above that the cycling casualty rate pretty much flatlined between 2004 and 2010. And that trend doesn't include 2011, which saw a 22% increase in fatal or serious cycling casualties, probably outpacing the growth in cycling journeys. Again, if the cycling casualty rate is so important, isn't the record of the last several years rather worrying?

I'll look at some of these issues in the next post, which is about what target should be set. For now, I'd encourage everyone again to read the proposed new plan themselves and respond to the consultation.