History and cycling's mode share in Amsterdam and London

This presentation by René Meijer of the City of Amsterdam has a useful chart showing the transport mode split in Amsterdam by the length of the journey.

I've tried to recreate it for London, using data from the London Travel Demand Survey downloaded from TfL's Romulus website*. It's not possible to make an exact comparison, for a few reasons:

• For London I use data on journey 'stages', which includes things like walking to the bus stop. It's not clear whether the Amsterdam data uses data on stages or on the main mode used for a trip from A to B.
• The journey distance categories are slightly different between the two cities.
• I've included motorcycle journeys in the 'car' category in London, but it's not clear whether or how they are counted in Amsterdam.

With those caveats in mind, here's the London chart.

Note, I've tried to use similar colours, so the reason there's lots of red in the Amsterdam chart and hardly any in the London chart is that lots of people cycle in Amsterdam and hardly anyone cycles in London. The difference is huge, and seems to be made up by a mix of more travel by car and by public transport in London for trips of between 0.5 and 10 km.

London's high public transport share for medium-length trips (predominantly bus until for trips of up to 6km and predominantly Underground/DLR thereafter) is striking, and I think a little under-discussed in the debate about growing cycling. We have a pretty wonderful public transport network that competes against cycling both in terms of attracting passengers and, in the case of buses, for road space. Even though there is definitely scope for huge growth in cycling with the right policies in place, this starting point probably means we're unlikely to match Amsterdam's modal share even for trips of the same length. Cities can't choose their history, and that can make a huge difference to their future.

* You'll need to request a password to access the full site.

Robocars will change everything, somehow or other

I've seen very little discussion in Britain about driverless cars (or, if you prefer, robocars), but plenty in the US (see this and this, for example). As this long article in the Economist says, the technology has come a long way in a relatively short time, and it seems inevitable that driverless cars will start grabbing sizeable market share at some point in the next ten or twenty years. As detailed in that article, the implications could be profound. Cars driven by machine promise to be significantly safer than the human-driven variety, mainly because they will have a better sense of their own surroundings and can be programmed to not take any stupid risks. In fact, some of the technology is already in use as 'driver assitance' add-ons for existing car models:

Volvo already sells a popular driver-assistance option called City Safety for around $2,000, for example. It slams on the brakes if a distance-measuring laser or camera detects a vehicle or pedestrian in the car’s path. City Safety can prevent collisions completely at speeds of up to 30kph (18mph), and at higher speeds it softens the impact.

The other reason that driverless cars will be safer is that many people will recoil at the very idea and demand draconian safety regulations to allow them on the street. For example, they could be programmed to drive below the prevailing speed limit on every street, and to have 'black box' devices recording camera,  sensor and movement data (the Economist says the latter is already a requirement for robocars in Nevada). Combine that with software that stops the car whenever a pedestrian steps in front of it and you would have a total revolution in city transport. Currently pedestrians and cyclists are afraid of cars because we don't know if they will stop for us, so we cede the streets to them. But if you knew that a car was not going too fast and would stop for you, what's to prevent you stepping out to cross the road in front of it? This is the kind of technology that would make the fantasised, pedestrian-ruled version of 'shared space' actually a reality.

Unfortunately, that's also the reason why all shared space schemes would probably be removed as quickly as possible. Nobody in a driverless car would want to sit there like a lemon while pedestrians merrily parade past in front of it. After all, if you clear the road of everything except other driveless cars these things will be able to go very fast. Roads that feature cyclists weaving in and out of traffic will be awful for robocars, while Dutch-style segregated lanes will be just peachy. So if the technology takes off, expect to suddenly see a lot of enthusiasm for roads that completely segregate cars from bikes and pedestrians.

Expect big changes in how we relate to cars too. Taxis might become either obsolete, if everyone owns their own robocar, or universal if nobody does (they just won't have taxi drivers). After all, taxis are expensive largely because they have to transport the taxi driver around the whole time even when there are no passengers. Eliminate that fairly hefty weight and they could become economical for everyday use, so why own your own?

The technology is likely to be transformative, in other words, but it's not completely clear in which direction (I haven't even mentioned the implications for inter-city transport, which are likely to be just as huge but more predictable). Maybe we will see cities sort themselves into two camps, one of which imposes speed limits on robocars and lets cyclists and pedestrians boss them around, while the other segregates uses, punitively cracks down on jaywalking and tries to speed as many cars through their streets as possible. The strange thing about driverless cars is that they seem like they could deliver almost every urban transport utopia you care to imagine, and some of the dystopias too. [Update: Speaking of which, by popular demand (two people on Twitter) here's Johnny Cab!

The amazing fall in urban crime rates, and the downside

The Economist has an article about the sharp decline in crime in American cities since the early 1990s, noting that there is no consensus over what caused it. This disagreement isn't that surprising since so many factors may be contributing to crime at once, and since the debate also has some ideological and political significance.

But it is really worth emphasising just how large has been the drop in crime in US cities, because it's important not just on its own terms but for what it says about where our cities are headed. The longest reliable historical record of crime in US cities is probably the homicide rate in New York City, which the late Eric Monkkonen compiled for every year between 1800 and 1999. You can find his data series here. It includes not just the number of homicides but the rate per 100,000 residents, and I have updated the series to 2011 with homicide data from the NYPD and population data from Wikipedia. 

I think there is good evidence for the theory that lead poisoning (from car exhaust and lead paint) had a lot to do with these trends, partly because it helps explain why crime rates fell not just in the US but across Europe too (see Kevin Drum on this subject, including relevant links). I'm sure improvements in policing helped too. But in a way what caused the fall in crime is less interesting than what knock-on effects it will have.

People understandably put a high value on safety and are willing to pay a price premium to live in low-crime areas. So you would expect the fall in urban crime levels to have contributed to higher urban house prices, and at least in the case of New York you would be right - this research estimates that falling crime rates explain about a third of the mid-1990s increase in NYC house prices.

These price rises show that people really value the safer urban environments created by lower crime. But higher housing costs may not be good news for everyone, especially tenants facing higher rents. If New York City had built a lot of new housing to cope with rising housing demand it would have been able to moderate (but probably not eliminate) these price increases and allow more people to enjoy living in a great city with falling crime rates, but instead higher demand fed straight into higher prices. It would be tragic if this pattern was repeated elsewhere and low-income people pushed out of cities just as they finally become more liveable.

Land values and urban history

Via the Urban Demographics blog, here's a short video of Dr Gabriel Ahlfeldt of the LSE discussing his analysis of a unique dataset of land values in Chicago over time. Apart from looking pretty, this kind of analysis is of great interest to urban economists since land values are both fundamental to understanding cities and very difficult to observe in practice, because the value of land is usually mixed in with the value of structures on it. The data Dr Ahlfeldt analyses manages to separate the two out, allowing us to see how much people are willing to pay for 'pure' location as distinct from whatever happens to be built there.

You can see from the video that land values are very high in Chicago's central business district but then drop off sharply as you move out, a sign that people will pay a very premium to locate their home or workplace (mostly the latter, in this case) in that spot. And as Dr Ahlfeldt says, that particular location has been far more valuable than any other in Chicago for the whole period covered by the data.

So even though vast numbers of boats carrying corn, lumber and pork no longer come and go via Chicago's small harbour on Lake Michigan, the legacy of that waterborne trade and the density of businesses and institutions that built up around it can still be seen in the pattern of industrial and commercial location today. This suggests a very important role for path dependency, history and perhaps chance in explaining urban form.

You can see the whole of Dr Ahlfeldt's lecture and many others at the Lincoln Land Institute here.

Nicer inner cities might be a mixed blessing for people on low incomes

Ben Rogers, writing in the Standard, gets to the heart of dilemmas around aspirations towards 'mixed communities' in the face of economic forces that seem to be acting against them. Read the whole thing, but here is an extract:

As property prices go up, lower earners will be squeezed out. In the absence of a massive house-building programme in central London, the capital will become to feel more like Paris, with a rich centre and a poorer outer-ring. Rent policy can slow or hasten this process but not reverse it.

Should we care? Instinctively I want to answer "yes". I look on with misgivings as the Highbury street on which I live becomes steadily fancier - even though I know that I have contributed to that process and stand to gain from it financially.

It has been an article of faith among socially-minded reformers since the days of Joseph Rowntree and Ebenezer Howard that "mixed communities" are a good thing and income segregation bad. Yet the evidence in favour of mixed-income neighbourhoods is weak. Poor children from rich neighbourhoods do not seem to do any better in life than those from poor neighbourhoods. LSE economists Paul Cheshire and Henry Overman argue that there might even be benefits for poor people living in poor neighbourhoods: shops are cheaper and public services tailored to them.

The evidence on the impacts of mixed communities is indeed fairly mixed, and the point about costs is an important one, but I'm not sure it's the whole story. If the cheaper areas of the future are going to be in the suburbs then the cost of transport for the poor to get to city centre jobs is going to be higher. School quality and environmental amenity are also likely to be lower in cheaper areas - that's part of the reason why they're cheaper, after all.

So I think the benefits to the poor of being 'squeezed out' of affluent city centres are still fairly ambiguous, even leaving aside the very large transitional costs facing anyone who does make such a move (as demonstrated by the fact that the people affected by the cuts to housing benefit generally seem pretty unhappy about it).

More broadly I think these dilemmas highlight a very important shift in how our cities function. To simplify massively, in the past when cities had lots of dirty industry they had dirty environments as a result, particularly towards the centre. That encouraged richer people to move out of inner cities as soon as they could afford to and transport allowed. On the other hand, poorer people could save on transport costs by living in the centre, close to the jobs but also close to the pollution.

But over time, as incomes rose and as environmental regulation strengthened, cities lost most of their dirty industry (and associated crime, perhaps). Inner city environments improved drastically, which meant that the rich have started to come back in, lowering their transport costs at the same time. That pushes up housing costs in the centre. So the poor have to choose between staying put and paying higher housing costs, or moving out and paying higher transport costs. That's if the poor rent in the private sector, anyway. If they own their own place or live in social housing, they get to benefit from an improved inner city environment without higher housing costs. So there's an argument that inner city social housing is of increasing benefit to the poor as city centre environments improve. You can also see why it's of increasing interest to those who think we should sell it off.

Obviously that's a very broad sketch with quite a few simplifications and assumptions thrown in[1]. But I think the link between 'greener cities' and displacement of the poor is real enough.

[1] E.g. it assumes that the centre still has the lion's share of the jobs, which is the case in many European cities but not in some US ones.

Affordability or amenity?

Rowan Moore reads the new enormobook 'Living in the Endless City' and fishes out a good quote:

Suketu Mehta, on Mumbai, articulates the fundamental dilemma of urban improvement. No matter how appalling the overcrowding and squalor might seem, the city will continue to attract yet more people because it still offers things, such as freedoms and opportunities, that the countryside cannot. And, therefore, according to a planner quoted by Mehta, "the nicer you make the city, the larger the number of people that will come to live there".

Now, on the one hand, that's extremely obvious. But on the other hand I'm not sure we always think through the implications.

Over the past few decades city centres in richer countries have generally become better places to live, as crime has fallen and dirty industries are either priced or regulated out [1]. So demand to live in city centres has also gone up. Faced with higher demand, cities can choose to increase supply (by building more housing and offices) or to keep things as they are.

If you increase supply you are changing the environment that people have come to value. People being risk-averse, it's not surprising that they tend to resist. But not increasing supply (or, more commonly, not increasing it enough to match rising demand) means that over time, improved quality of life feeds into higher prices for housing and commercial space. Which is exactly what we have seen happen in Manhattan, and what I think is happening in London.

So cities with improving environments have a decision to make: if they try to keep their city affordable, they need to make some big changes to its built environment just as people start attaching a greater value to the status quo. Economists sometimes act like this is a no-brainer, but it really isn't. I think that people become more resistant to change in the built environment (i.e. to new housing or office supply) as its amenity value increases, and you can see why. But the implications for the long-term affordability of city centres are very serious.

[1] These two trends are two sides of the same coin, if you buy the argument that falling lead pollution caused falling crime rates - and I think I do.

Spaces for cars, spaces for people

At some point early in the previous decade, Britain reached what I think should be considered a significant landmark. The number of licensed private cars in the country surpassed the number of dwellings for the first time: in 1961 there were three dwellings per car, in 1981 1.8, and by 2008 it was 0.98 (though showing signs of stabilising).

Obviously a car is a great thing to have for many people, if they can afford it, and as incomes have grown more people have found it a worthwhile investment. But a decent, affordable home is a good thing to have too, and I think it's interesting to contrast our enthusiasm as a society for allocating more and more space for cars with our hostility towards allocating more space for people to live in, as well as the very different government policies applied to each case.

Considering how expensive and cramped the housing in much of the country is, you might expect society in general and the various levels of government to be constantly striving to increase the housing stock. But what you actually see is amazingly energetic and committed grass-roots efforts to constrain the growth of the housing stock, which are then reflected in a very restrictive set of government policies. By contrast, people and government in most parts of the country seem united in their determination to increase the amount of car parking available. It's rational for every individual to want cheap parking for themselves, but the aggregate consequences are fairly perverse: you end up creating places like Hungerford and many similar towns around the country, where there are strict controls on using land for anything except car parking, so that car parking is made cheaper and everything else more expensive.

The growing number of cars is using up more of our time as well as more of our space. The more cars there are on the road, the more congestion there is and the more time each car spends sitting in traffic. And because both space and time are strictly finite resources, the opportunity cost of space and time given up to cars is only going to grow if incomes continue rising over time. We seem to be acting with a collective assumption that allocating more and more space to cars is a costless decision, but it really isn't. Over time we have turned many of our streets from places of movement into places for storing large metal boxes - just because the change has happened gradually doesn't mean it doesn't have very important consequences, many of them negative.

In short, I think the growth in the number of cars represents a significant resource problem for our society, one that seems to be receiving roughly zero strategic attention at the moment. What to do about it is an argument for another day: in general I think a combination of supply caps and market pricing would help a lot, but as we haven't even started having a debate about the issue yet any reasonable policies seem a long way off.

Sources for the graph: Private cars licensed from Department for Transport table VEH0103 here, number of dwellings from DCLG table 102 here.

Urban myths and the misuse of urban data

Following up my post about the mismeasurement of urbanisation in Egypt, I would highly recommend anyone interested in this area to read David Satterthwaite's article on 'Urban myths and the mis-use of urban data' (pdf).

Satterthwaite's article covers a lot of ground, including alarmism over 'out of control' urbanisation in Africa, the extreme paucity of census data in some areas, and problems in measuring city size and therefore various indicators of city performance. But I'm going to focus on his discussion of how the comparability of the UN's urbanisation statistics is undermined by the use of different definitions of urbanisation at country level. For example:

China’s level of urbanization in 1999 could have been 24 per cent, 31 per cent or 73 per cent, depending on which of three official definitions of urban populations was used. India appears to be a predominantly rural nation, but most of India’s rural population lives in settlements with between 500 and 5,000 inhabitants, which are considered as villages and therefore classified as rural; many more live in settlements with more than 5,000 inhabitants, which are still classified as rural. If these were classified as ‘urban’ (as they would be by some national urban definitions), India would suddenly have a predominantly urban population. 

And then there's Egypt:

in 1996, 18 per cent of Egypt’s population lived in settlements with between 10,000 and 20,000 inhabitants that had many urban characteristics, including significant non-agricultural economies and occupational structures. These  were not classified as urban areas – although they would have been in most other nations. If they were considered urban, this would mean that Egypt was much more urbanized, causing major changes to urban growth rates.

Remember that Egypt's central government had an incentive to systematically under-estimate its urban population, as granting city status to an area meant allocating it more funding and representation in parliament.  

The lesson here is that people should be careful about using data on cross-country comparisons, they should be extra careful when it comes to data on topics like urbanisation where there is no standard definition, and they should probably be extra extra careful about data that is produced by governments like Egypt's. After all, if your argument is that the Egyptian government is dysfunctional, then shouldn't you be at least slightly sceptical about the data that government produces?

Ed Glaeser at the LSE

Ed Glaeser spoke at LSE on Monday night as part of a tour plugging his new book, Triumph of the City. With his slightly ship's-captainy appearance, extravagant gestures and SUDDEN CHANGES IN VOLUME, Glaeser makes for an entertaining speaker and a great salesman for cities, which seems to be the role he has settled on.

His talk was focused on the central message of his book, i.e. the benefits of dense urban areas and the costs of anti-density policies. On the benefits side, he made a convincing argument that better communications technology makes cities more rather than less attractive places to work, because by making routine communications easier they increase the returns to the much richer face-to-face form of communication. This is more true in some industries than in others, and one in particular: Glaeser says "There is no industry in which knowing a little more is worth a lot more than in finance", so for better or worse we shouldn't expect financial services to lose their dominant role in New York or London any time soon.

Another key benefit of density, which after all is just proximity in another guise, is that it allows people to save on transport costs. This, said Glaeser, is the main reason why you tend to see so many poor people in big cities. Their housing costs may be high but their transport costs are low, on top of the greater economic opportunities on offer. So maybe the high measured levels of inequality in cities isn't such a bad thing: in fact, Glaeser declared that there is "more of a problem in the artificial equality of suburban areas than in the inequality of urban areas", which is certainly something to chew over.

The economic benefits of agglomeration have always favoured cities, but high population densities can bring significant costs, most notably in terms of disease, congestion and crime. Life expectancies and general health used to be much worse in cities like New York and London than in the countryside, but thanks in large part to huge public investment in sanitation (and, I would argue, transport improvements that reduced overcrowding in the very centre) the gap has closed and in some cases reversed. Public health is still a huge problem in some of today's megacities, but Glaeser is convinced that similar investments can make all the difference.

Cities in rich countries are today generally much safer places than they used to be, with crime levels having fallen in most countries since the 70s and 80s. Glaeser noted that workers used to effectively get a 'real wage premium' for enduring New York's awful conditions, but now it is the other way around, with people willing to pay huge prices for the privilege of living in formerly bohemian areas like Greenwich Village.

At this point Glaeser had some criticism for Jane Jacobs, who he thought was unduly hostile to densification in her Greenwich Village neighbourhood and places like it. When Jacobs lived there the Village was an attractive, human-scale, organically 'mixed community', and Jacobs wanted it to stay that way. But Glaeser contends that a lack of sufficient new housing supply meant prices in nice, central places like the Village went through the roof, with the result that it is now a profoundly un-mixed community where only hedge fund multi-millionaires can afford to live.

I've got a few comments on this last issue, as I think it's fairly critical for cities like London which are trying for economic growth without excluding the poor and middle classes. The first is that it seems to be more or less impossible to preserve both affordability and the existing neighbourhood built form in the face of strong housing demand: you've got to choose one or the other.

The second point is that the relationship between the two is unstable - after all, if the reaction to a big increase in demand for housing in, say, Islington is to build a huge number of flats, then it isn't the same place it was before and a lot of that demand may disappear, potentially leaving you with a supply overhang and a less attractive environment. That's probably an extreme example as housing supply is never that responsive, but the point is that economists don't seem to me to have a good handle on these interactions as yet.

Lastly, it's fine to argue that places like Greenwich Village shouldn't have made the mistake of restricting new housing supply, but that doesn't answer the question of whether it is possible to undo the 'damage' now that it has become an enclave of the super-rich. Is there really any chance of persuading such a group of local residents to accept major structural change to the area they have paid so much to live in? This matters because if the answer is no then new supply won't be in areas like the Village but in less desirable places, probably more distant from where people want to be. If that's the case, then the very attractiveness of cities may undermine some of their economic and environmental benefits.

The mismeasurement of urban Egypt

The short version of this post is that despite recent reports, urbanisation in Egypt has not gone into reverse in the last 30 years. The Egyptian government systematically under-estimates both the size of and the growth in Egypt's urban population for adminstrative/political reasons. For the full story, see below the fold.