Where Do People Meet? Urban Segregation in Cellular Data

Ott Toomet, Siiri Silm, Rein Ahas, Erki Saluveer, Tiit Tammaru

Immigrants and ethnic minorities often live more or less separately from the majority population. This fact is sometimes touted as a major problem that hampers social integration. But does the place where we live actually matter? Anecdotal evidence suggests that we do not interact much with our neighbors. Why should we worry then who they are?

To shed more light on this issue we analyzed the spatial behavior of Estonian speaking and Russian speaking population in Tallinn, Estonia. It is an interesting city as it is almost 50-50 split between the corresponding ethnic groups. We used cellphone data for the analysis. Mobile operators always record which antenna talks to our phones, and such data essentially form a spatial track of our activities where one can see our approximate location and time. It is relatively straightforward to analyze the tracks and deduce who were close to each other, and when and where it happened. Looking at the repeated patterns of calls we can also guess where people live and work. In this way we can see who can potentially meet each other, and where such meetings might occur.

So, are Estonian speakers close to Russian speakers in Tallinn? Well, it depends on when. We find that when at home and at work, both groups are substantially segregated. However, this is much less true when people are elsewhere and busy with other tasks, such as shopping, but also during various leisure-time activities. Even more, such free-time segregation is not closely related to the environment in the place of residence and place of work (see the figures). Even those who live in almost completely Estonian or Russian neighborhoods experience a rather mixed free-time environment.

Fig 1. Relationship between free-time meetings and composition of residential neighborhood. Circles and triangles represent the averages across different neighborhoods. For Russians (red triangles), the percentage of Russian speakers ranges between less than 10% to almost 80%, for Estonians (black circles) between 20% and almost 100% (horizontal axis). Despite of living in such different neighborhoods, during free-time both groups meet own-group members for approximately 50-60% of the time.

Fig 2. Relationship between free-time meetings and composition of work neighborhood. The message is similar to that in Figure 1: work neighborhoods vary a lot, but it is not closely associated with our free-time environment.

What do these results tell us? There are several interesting conclusions.

• residential segregation may be less of a concern than often suggested. We spend much of our active time elsewhere, and much of the time we are at home we sleep.
• As a typical European city, Tallinn has a dense urban core where a substantial part of these meeting occur. It suggests that a dense vibrant downtown is favorable for bringing together people of different background. The results for Los Angeles may well be different.
• Finally, we do not know what is behind these meetings. Most of these are probably related to just being close to each other in a crowded city. But so are our relations with our neighbors: most of them we would not even recognize on street. There is need for more analysis on what are the "meaningful places" in terms of where do we actually socialize with people.

The full article is available at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0126093

Mediterranean Migration Crisis: Do Not Blame the Smugglers...

The recent disasters in the Mediterranean have brought immigration and human trafficking to the top of European agenda. EU has responded with a predictable face–lifting proposals—promising to
triple the maritime patrols and tackle the issue "at its root", by attacking human traffickers, and by improving the border policing of the African states (in particular Libya).

But this is not the root of the problem. The main underlying problem is the world inequality, both in humanitarian and economic sense. Too many people are living in a desperate situation, be it because of threat to their lives, or lack of opportunities in the place where they happen to live. And for these people, the smugglers are simply the least bad of the available options.

I stress this again---the traffickers are the best available option for hundreds of thousands of migrants. All these people hope that the traffickers help them to escape death and poverty, and to fulfill their dreams of a better life. They are willing to pay an amount, comparable to the price of Europe-US return flight in business class. What they get for it is a 90-percent chance to cross 200km of sea in a crowded wreckage. Remember also that these people cannot just save this money from their paycheck over a few months, for many of them it amounts to years' of savings. This should remind us what scale of human suffering is out there behind our borders, how desperate are refugees, and what is the role of the smugglers.

This is not to say that the smugglers should not be blamed at all. They still must treat their "customers" in a humane manner. They should inform the migrants about the dangers and opportunities of the trip. They must keep their promises. Slaughtering selected people because of religion or other reasons is plainly criminal. Smugglers should also follow minimal safety and navigation standards. But these problems can be addressed by training, regulation and oversight of the smuggling industry, not by airstrikes. Or even better—by opening a regular ferry line that adheres to the accepted safety rules.

The initiative to improve the border patrolling and crack down the human trafficking in African countries is more like outsourcing the border guarding jobs further away to forces with more dubious human rights record than the European ones. It will not help with the underlying problems, and it will increase human suffering by leaving hundreds of thousands in a desperate situation without the best option to escape they have had up to now. To really address the root cause would mean to ameliorate world inequality, and to pacify Middle-East. This is far beyond what EU (or anyone else) can realistically hope. Unfortunately, the simple and realistic alternative—open the borders to substantially more refugees—will enjoy very little popular support.

So, dear politicians, I understand very well that tackling the root of the problem is simply a fantasy. I also know that the voters do not let you to take any available steps either. But you still can use the right words: Our response will be to build a stronger fence. Because suffering further from our borders is not our problem.

Water Markets for California

California is parched.  There is little water and all the forecasts indicate that there will be even less of it later in summer.  What are the options to ameliorate the situation?

There is one obvious reform that has not received much public attention: introducing water-markets.  I do not understand why is the market solution almost universally overlooked.  I am even willing to argue that water market is the solution, it may be supplemented with other means but those will remain supplements, adjusting the market where it cannot get it right.

This is not the first dry spell in California.  Dry riverbed in 2009.  By NOAA, [Public domain], via Wikimedia Commons

Instead of markets, we hear about different ad-hoc measures.  But how much can a state save if the restaurants are forced not to serve water to the customers unless they ask for it? Who is going to control whether lawns are watered 2 or 3 days a week?  Why do we need rules that only permit to fill covered pools?  The list goes on-and-on, garden fountains can only be used in case they work on a closed circulation, cars can only be washed with hoses with shutoff nozzles, new developments cannot irrigate with potable water unless drip irrigation systems are used, agricultural water users have to report more water use information to regulators...

There are several issues with such measures.  First, these may not be effective for saving water.  The problem is not washing streets or watering lawns after rain.  The problem is that the population as a whole uses more water than what is available.  It is the total quantity, not the way water is used.  We may prescribe what is the "fair" use but wasteful usage remains an issue even when only spending water in "acceptable" way—we cannot check how many minutes people take shower.  Second, the government cannot decide what is the best use.  Water consumption does not have noteworthy externalities, so it should be left to the individual users to decide what to do with it.  Third, such measures may target the straw-man while leaving the main culprits untouched.  The little data I have suggests that more than 3/4 of water in California (out of what humans are using) goes for irrigation.  As a rule of thumb, agricultural water need is around 1000 times the final mass of the harvest.  So, the "water-tag" of a restaurant meal amounts to 300-1000kg, out of which less than 1/1000 is served in glass...  Maybe we should ban restaurants to serve Californian rice instead?

Markets help to settle all these issues.  Here is a number of steps one has to take to reach fully functioning water markets.

• Clear water property rights.  The water ownership must be unambiguous, both for reservoirs and groundwater. 
• Extraction quota for different water sources, set each year by a public institution.  Up to the quota, the owners can sell water to any user.  This amounts to a "cap-and-trade" system.
• The quota must be tradable.
• "Pipe-neutrality".  The price must be associated with quantity,  quality, and location of the water, but not how it is used.  If you pay the price, feel free to drink, water your lawn, or wash the car.  Note that this is exactly how the electricity market works.
• Every household and farm must have water meters.  This also applies to irrigation water.
• There may be a need for a (temporary) support for those who loose as a result of the new system.  The support must be in the form of cash, not water!

Water meters are simple and ubiquitous.  Photo: André Karwath aka Aka [CC BY-SA 2.5], via Wikimedia Commons

Who are the loosers?  Many will point to farmers but that depends on who will obtain the water rights.  If the farmers will be entitled to a large endowment as they have historically been, they may be the winners instead—selling that water may bring more income than using it on fields.  If, however, the rights are given to someone else, many farms will be immediately out of business.  It is expensive to farm in arid climate.

Finally, I stress here that this reform does not amount to a tax hike.  First, the money for water goes to the government only if the government gets the water rights.  Second, if this is the case, the government should lower taxes, such as income or property tax.  It amounts to shifting government revenues from property and income tax to natural resources.

Tax Breaks for Protecting Landscape

Untouched nature is increasingly scarce.  This is even more true close to big population centers where such areas are of high value. Below I talk mostly of  forests but the ideas are more general.

Old forest.  Many snags and coarse woody debris offer habitat for a wide range of organisms.  Such forests are often suitable for recreational use as there is little undergrowth due to dense canopy above.  Conifer forests of Rattlesnake Ledge, WA

Land is typically taxed based on it's market value.  This approach is simple—it only depends on the size and location of the plot (although determining the value may be tricky).  However, it does not encourage the landowners to preserve the valuable habitats, nor does it encourage it to keep the land open to public.  It implicitly tells that the property owner is the sole decision-maker and does not have to take into account the others' interests.  But natural landscape is valuable not just for the landowner but also for other users, such as leisure trekkers or picnickers, and for many living organisms other than homo sapiens.  In economics parlance, natural landscape possesses positive externalities.

Keeping land open for everyone—for both nature and humans—should be an attractive option.  It can be encouraged by making land tax dependent on the type of usage.  Valuable natural habitats where the public has open access should be free of tax.  In other words, we should not tax land possession but only the "exclusion" of land, using it in a way that does not permit the others (including nature) to benefit from it.

Private property: Harvested natural forest is replaced by a plantation.  The area is made inaccessible both for humans and for large animals.  (Former) temporal forest in Veskimõisa, EE.

This approach will bring a number of changes:

• The landowners should only pay land tax on such a property that is either not open (like gardens and courtyards) or not natural (like fields).  Forests, natural meadows, and other habitats should be considered as "natural land".  If everyone has free access to these areas and human interference is kept at minimum, the land should be tax-free.  I mean "free access" in legal sense, the owner should not have any obligation to facilitate it through specific infrastructure.
• In case the landlord takes some of the natural area into non-natural use (say, by logging), then it will immediately be subject to tax.  The tax will decrease over time as the nature take over and the natural/leisure value of the area increases.
• Analogously, if land that was previously used for non-natural or restricted purpose is left untouched, the tax will fall over years as the value of it grows.
• If land tax is based on the market value, it implicitly (albeit imperfectly) takes into account how the human value of land depends on location.  Land near the population centers is expensive, and hence the potential land tax will be high.  Such a tax exemption encourages creation of publicly open natural areas close to cities more than it does that in far-lying locations.
• In order to be eligible for a lower tax rate, the natural value of the land must be re-assessed. The landowner should apply for re-evaluation, perhaps no more frequently than once in 5-10 years.  Such evaluation reports should be made public to decrease the room for corruption.
• Perhaps the largest problem with this proposal is the need to asses the non-market value of land.  It is a vague concept and leaves room for interpretation.  Simpler but less precise rules may be preferred instead.

Natural resources are a strong incentive to restrict public access.  Diamond area in South Africa, 1940s.

Who are the winners and the losers?  First, I don't think this measure would be massively used and hence the effects will be small. If it will, however, it may harm the logging and wood processing industry. Second, if the tax income from certain plots decreases, it must rise elsewhere (not just on land).  So it amounts to trading more nature for higher taxes.  Obviously, the winners are those who benefit from the nature and the losers are those who do not.  Finally, the largest gains are experienced by property owners who already keep their natural land open for everyone.

Veeriku-Näituse-Downtown: A Functioning Pedestrain Highway in Tartu

Tartu is not the best place to move around on foot.  Although not a big city in terms of population, large business areas are impractically far for pedestrians, and there are few convenient options to cross roads, the river and the railway even in the urban core.  It also seems like the municipality has little clue what makes pedestrians thrive in the city.  But Tartu has examples of rather well functioning solutions.  One of these connects Veeriku neighborhoods over Näituse street to the inner city.  This route includes many such details that make a street a place where people thrive.  It also includes a number of obstacles, many of which can be easily fixed. Let's start from Veeriku.

A number of streets merge at the far end of Näituse making it the shortest route to downtown for many residential neighborhoods.  There are not too many cars and the sidewalks are of adequate width and quality.

 Far end of the Näituse street.  The sidewalks are wide enough and good enough here given the moderate number of cars.

 Unfortunately, the sidewalks turn less-than-adequate rather soon.  Up to the railway crossing, they are muddy and too narrow.  This is partly because of broken pavement, and partly because of the potholes in the roadway.  The situation might be acceptable for an unimportant street but not for such a central "pedestrian thoroughfare."  These problems are easy to fix by widening and improving the pavement.

Näituse street approaching the railway crossing.  The walkway suffers from broken pavement that renders it rather narrow on rainy days.

The first real bottleneck is the railway crossing.  One can easily see two problems: first, both ends of it are muddy and unpaved, and second, the sidewalk is too narrow between the tracks.  In places, the walkable width is only about 0.5m, far too little for this much walked route.  The main roadway is very close to the walkers with virtually no separating barrier in-between, but as the rails are not suitable for driving at full speed, the pedestrians are saved from the worst of the motorized traffic.  Fortunately, it is plenty of space here to widen the footpath.  Note also that as only the left-hand-side of Vaksali street (when looking toward the inner city) has a pedestrian crossing, that side is perhaps more important than the other.

Näituse street railway crossing.  The sidewalk is too narrow, and of too low quality at both ends.  It can easily be widened here.

Across the rails, the street is beautiful, tree-lined and with a separate footpath.  This is very nice.  The pavement is of sufficient quality for walking (but not for cycling).  My main complaint here are the parking cars: too often they occupy a substantial part of the walkway.  This may be acceptable for unimportant streets, but on such a major route the motorists should show much more respect for pedestrians.

A car on the sidewalk on Näituse street.  For most walkers this is a little obstacle but it substantially disturbs cyclists.  Note that there is enough space in front of the car to move it out of the walkway.

The final part of Näituse street, down from Kastani, suffers from somewhat narrow sidewalks.  Fortunately, a lot of pedestrian traffic heads to the other areas and cars are slow.  Further downhill, behind the wonderful Kassitoome, the sidewalks are just ridiculous.  In the lower end of the Baeri street, the right-hand side is far too narrow even for a single walker, and often cars are parking just next to it.

A sidewalk that is just plainly too narrow. Baeri Street.

The same is true around the Krooks pub: both sides are too narrow given the large number of pedestrians here.  In this place the street is substantially more important than in the beginning of our walk as it also connects Tähtvere and Supilinn neighborhoods with the downtown.  Wider sidewalks are needed.

Jakobi street in front of Krooks pub.  The sidewalks are inadequate and pedestrians are forced to stay very close to cars.  One should narrow the roadway, give more space to walkers, and install a speed table here.

The last obstacle, Jakobi-Lai crossing, recently got an adequate solution, although I was in favor of shortening the turn radius instead of installing the traffic islands.

It is rather easy to fix many of the existing problems. At the further end of Näituse street, one could simply widen the pedestrian area and pave it adequately.  There is plenty of space for it.  In the inner part of the city, this is not possible without squeezing the motorized traffic somewhat.  It is acceptable in my opinion, even in front of Krooks. One can remove one or two parking lots at the upper side of the street (these can potentially be moved over to the lower side) and widen the sidewalks on both sides by 0.5m.  This would roughly double the walkable width and make it a much more pleasant place. It is also a good idea to install a speed table to slow down cars driving so close to pedestrians.  Finally, parking on pedestrian areas must not be the default option.  If really necessary, one should take all the possible measures to avoid obstructing pedestrian traffic.

Splitting states: Donbas and Scotland

I am often not happy that "territorial integrity" and "sovereignty" are considered valid arguments against separatism.  I think that regions should have an option to separate from the country they are part of, and eventually merge with another country. This also applies to Crimea and Donetsk.  But such a separation must fulfill a number of criteria.

First, the decision must be democratic.  Democratic decision is not a hasty referendum.  It is a long open process where the idea of independence is brought up, pros and cons discussed, and more-or-less stable opinion formed.  I don't know what might be a relevant time scale here but I suggest a few years at minimum.  It is definitely more than a few weeks.

The democratic decision also means the media is free to report, and all people are free to express their opinion.  If some parties cannot do it because of threats, abductions and killings, the process is not democratic and the results of the related referendums questionable.  Potential separatists should be very much interested in demonstrating to the outside world that the support they claim does not "grow out from the gun barrel".  Unfortunately, in Eastern Ukraine they rather demonstrate the opposite.

A bad example of separatism.  "Little green men" at Simferopol airport, 2014-02-28.  Crimea was literally taken at gunpoint, no negotiations with Ukraine were conducted.

Third, separation must be negotiated with the former mother country. In general, a region that strives to independence is eligible to a share of the national assets (including the military ones) but should also inherit a part of the national debt.  On top of that, one has to agree on thousands of everyday details like cellphone rates, bank transfers, public pensions and education certificates.  All this must be ironed out, preferably some of it already before the independence referendum, to give the voters a better picture what they are choosing between.

None of these criteria were followed in Crimea and in Donetsk. That's why I am against separatists there—not because of the Ukrainian territorial integrity.

A road to another region with raging separatism.  No checkpoints, no gunmen here. 

But we also have good examples of separatism.  Scotland will vote on independence on Sept 18, 2014.  This date has been put forward one-and-a-half years in advance after a debate that has lasted for decades.  All pro-independence politicians realize that eventual separation goes hand-in-hand with long negotiations with the (rest of the) UK, and no-one is proposing to set up checkpoints at Tweed river.

What makes good bicycle tracks

I have already written here that most bicycle tracks in Tartu are of unacceptable quality.  Too often they are not direct, not smooth, and in places too narrow.  As it seems, the planners do not understand the basic needs of cycling.  Here I explain a little.

Bike track in Aarhus, DK.  It is smooth, and it goes straight across the junction.  The same priority rules apply both for cars and cyclists.

First, safety is important but not all-important.  I have seen claims that safety is almost the sole characteristic of the bicycle traffic. This is simply not true.  Bike tracks are not (just) about safety. They are about a combination of safety, accessibility, smoothness, and speed.  If safety were the all-important requirement, we would never cycle, never walk nor even drive small cars.  But we do.  We accept a low risk of injury if this helps us smoothly to get where we want to go.

Junction of Riia and Raudtee streets.  The bicycle track ends here abruptly at a guardrail (center).  The cyclists are supposed to take a sharp turn right, then left, cross the street at pedestrian speed, and continue on a very narrow sidewalk (right).  It is a safe but very inconvenient solution. A car lane at the same place (left) has neither abrupt turns nor other obstacles.  As the street goes downhill, cyclists can easily achieve speeds here comparable to those of cars.

In order to improve the biking conditions, one must plan the lanes with this suitable combination in mind.  If cycle lanes are very safe but the ride will not be fast and smooth, people will not choose cycling (or choose to cycle elsewhere).  In practice, the picture is complicated by the heterogeneous preferences by cyclists.  Broadly, kids and slow rider prefer safety, fast riders smoothness.  But it is perfectly possible to cater to all of them in most cases.  Usually it is achieved through street hierarchy—slow speed is enough inside a city blocks but large thoroughfares should allow full speed cycling (at least 30km/h).  Cyclists are exactly like motorists from this aspect.

Left: bike track between Maarjamõisa hospitals and University biomedical center.  Except for a few curbstones, this stretch is adequate for short-distance connection inside the university campus.  Due to it's location, it cannot be upgraded for high-speed connection between different parts of the city.  Right: bike track next to a major thoroughfare, Võru street.  Unlike cars, cyclists are supposed to yield at the small sidestreet and take an inconvenient turn just after the junction.  This is a place where the track should be upgraded to allow full-speed cycling.

Second, road users are always interacting and have to adjust to other road users.  This is partly achieved through planning of roads and junctions.  It is important to realize that adjustment is costly, usually involving breaking and speeding up again, and often maneuvering.  Current cycle tracks put too much of these adjustment costs on cyclists.  The tracks almost never go straight across intersections, even at the main thoroughfares, often forcing bikes to slow down to walking speed in order to cross curbstones and take sharp turns.  Second, instead of dedicated bike lanes, cyclists are often expected to ride on pedestrian walkways.  This is an acceptable solution only if these are wide and not crowded.  The most critical points are typically bus stops, turns around street corners, and areas near pedestrian crossings.  Sidewalks in these places are often narrow, visibility low, and many people standing and waiting.  Now compare this with the car lanes at the same stretches.  Those almost always retain their width, there are hardly ever obstacles like curbstones, and they go straight across the junctions.  Most of the the adjustment costs are shifted to cyclists and pedestrians.

Seems like the planners mainly follow two aims: the lanes must be safe, and the motorists should not bear the adjustment costs. Unfortunately, this leads to unusable cycle tracks.