Sustainable City Lab

Features are easy, defaults are the work

Ask what makes a city sustainable and most answers list equipment: solar panels, recycling bins, a cycle lane. Those are features, and a feature changes what is possible. What actually changes a city is the default, meaning the option people take without thinking about it, because that is the one almost everybody takes. The district of Vauban in Freiburg is the clearest example there is. Built from 1998 on a former barracks and now home to roughly 5,500 people, it does not ban cars. It unbundles them: a parking space is not included with a home and has to be bought separately in a garage at the edge of the district, while the tram stop, the shops and the schools are within walking distance. Nothing is forbidden, and around 70 per cent of households own no car, against a German average near 550 cars per thousand people. The cheap and obvious choice changed, so the behaviour changed. That gives you a question to ask about every scheme in this topic, and it is worth far more than a list: what did this change about the choice people make without thinking? A cycle lane that ends at a roundabout changed nothing. A flat bus fare that makes the bus cheaper than driving from the outer suburbs changed everything. Two more tests follow in this module: whether a scheme holds up environmentally, economically and socially at the same time, and where the problem went if it did not actually disappear.

Six terms, and the second is the whole argument

The second and third are the ones that turn a list of green features into an explanation of why a city changed.

How a car-free district is actually built

Six decisions turn a housing estate into a place where most households choose not to own a car. Put them in order.

• Choose a site close enough to the city that walking and the tram are realistic
• Put the tram stop, the school and the shops within walking distance of the homes
• Sell parking separately from the housing, in garages at the edge rather than at every door
• Let the true cost of a space show up in the decision, so owning a car becomes a choice with a price on it
• Design the streets for people first, since without through traffic the space between the houses becomes usable
• Provide car sharing for the journeys that genuinely need a car, so giving one up is not giving up mobility

Why is a solar panel not the answer?

A council fits solar panels to a block of flats and describes the estate as sustainable. Which is the strongest objection?

• Because equipment changes what is possible while leaving untouched what residents do without thinking. The panels cut some electricity from the grid, and if the easy choice is still to drive everywhere, to heat a poorly insulated flat and to throw everything into one bin, the pattern of daily life is unchanged. Sustainability is a property of the system rather than of the fittings bolted to it.
• Because solar panels are too expensive to be worthwhile.
• Because there is not enough sunshine in the UK for solar panels to work.
• Because manufacturing the panels causes pollution, so nothing is gained.

Five areas, judged by what they moved

The specification names five areas of urban sustainability. Each column below gives what the strategy does, a named scheme with dates and figures, and the default it moved, because that last column is where the marks are.

Match each scheme to the reason it works

Two questions that turn a list into an evaluation

Almost every answer on this topic lists green features and stops. Two questions turn the same material into an evaluation, and both are one sentence each. The first is the three-legged test. Does the scheme hold up environmentally, economically and socially at the same time? A measure that cuts emissions and prices out the people it was meant to serve has failed, and so has one that is admirable and unaffordable to run. Naming which leg a scheme stands or falls on is evaluation in a single clause, and it is why a flat fare is a stronger example than a fleet of electric buses: the flat fare is deliberately designed so the people furthest out, who generally have least, gain most. The second is the one almost nobody reaches. Where did the problem go? A scheme that moves an impact somewhere else has relocated it rather than solved it. Recycling collected here and shipped abroad has been exported. Traffic pushed off a charged street onto the boundary road has been displaced. A neighbourhood greened until rents rise and the residents it was built for leave has improved a place by replacing the people in it. Asking that question of your own example, and answering it honestly, is a grade-9 habit. And keep the figures attached. A named scheme with a date and a number beats the same point made in general terms every time.

Complete the sustainable city figures

The Freiburg district built from 1998 on a former barracks houses roughly 5,500 people, and because a parking space must be bought separately from the home, about _____ per cent of households there own no car. Curitiba has run its dedicated bus system since _____, on a single flat fare, and raised its green space from under one square metre per person to roughly _____ square metres. London began charging drivers to enter its centre in _____, and traffic entering the zone fell by around 15 per cent in the first year. In the UK a household uses about _____ litres of water per person each day, a figure that typically falls by a tenth or more once a meter is fitted.

Spot the three sound sustainability statements

Select the THREE statements that could stand as they are in an answer.

• Selling parking separately from housing forbids nothing, but it makes a cost that was hidden inside the price of the home visible at the moment somebody decides, which is why so few households there keep a car.
• A single flat fare favours passengers travelling furthest, who generally have least, so the scheme holds up socially as well as environmentally.
• Recycling that is collected locally and then shipped abroad for processing has moved the problem rather than removed it.
• Fitting solar panels to existing housing is enough to make an estate sustainable.
• The most effective way to cut car use in a district is to ban private cars from it entirely.
• Adding parks to a deprived neighbourhood improves it for the existing residents with no drawbacks worth noting.

A 9-mark evaluation, marked

Evaluate the effectiveness of strategies used to make urban areas more sustainable. [9 marks] The most effective strategies change what residents do without thinking, rather than adding equipment to what they already do. The district of Vauban in Freiburg, built from 1998 and now housing around 5,500 people, sells homes without a parking space, so anybody wanting a car buys a place in a garage at the edge of the district while the tram stop and the school are a short walk away. Nothing is prohibited, but the cost of a car appears at the moment of choosing rather than hiding inside the price of the house, and roughly 70 per cent of households there own none, against a German average near 550 cars per thousand people. Compare that with fitting solar panels to an existing estate, which reduces the electricity drawn from the grid and leaves every daily habit exactly as it was. Effectiveness also depends on holding up on three fronts at once. Curitiba's dedicated bus network, running since 1974 and carrying around two million passengers a day at its peak, works environmentally by taking cars off the road and economically because dedicated lanes cost a fraction of building a metro. Its single flat fare is the part worth dwelling on, because a passenger from the outer districts pays what a passenger in the centre pays, so the people with least income gain most. Its waste scheme from 1989, exchanging food and bus tokens for bagged rubbish in streets no lorry could enter, works the same way, solving a collection problem and a poverty problem with one measure. The limits are equally instructive. BedZED in Sutton, 82 homes completed in 2002, was designed around insulation and orientation rather than bolt-on equipment, and its measured savings still came out below the design figures, which is a reminder that a scheme has to be judged on what it achieved and not on what it promised. More seriously, some strategies move a problem instead of removing it: recycling shipped abroad for processing has been exported rather than dealt with, traffic charged off one street reappears on the boundary road, and greening a deprived neighbourhood can lift rents until the residents it was built for leave. Overall, the strategies that work are those that change the cheap and obvious choice and that survive all three tests. Equipment helps and settles nothing on its own. What earned the marks: three named schemes with dates and figures; mechanisms explained rather than policies listed; the social leg treated as seriously as the environmental one; an honest limitation drawn from measured results; and the question of where a problem goes asked and answered.

Find the two that would cost marks

Five sentences from answers on urban sustainability. Two would lose credit for the argument they make rather than for being factually wrong. Tap those TWO.

• The city is sustainable because it has solar panels, recycling bins, a cycle lane and several parks.
• Charging separately for a parking space makes a hidden cost visible at the moment of deciding, so fewer households keep a car.
• Collecting waste for recycling removes the problem completely, wherever the material is later processed.
• A flat fare benefits passengers travelling furthest, who tend to have least, so the scheme works socially as well.
• The measured savings at the development fell short of the design figures, so it is judged on what it achieved.

Build the mechanism sentence

Assemble a sentence that explains a strategy instead of naming it.

Four decisions on a city council

Each is a real choice. Apply the three tests rather than picking the greenest-sounding option.

• A council has a budget to make one housing estate more sustainable and is offered a package of solar panels for every roof.
• A transport authority can either lower fares in the city centre or introduce one flat fare across the whole network.
• A charge on driving into the centre cuts traffic there, and counts on the boundary ring road rise sharply.
• A new linear park is proposed through a deprived district, and local rents in comparable schemes elsewhere have risen sharply afterwards.

Evaluate the strategies

Using named examples, evaluate strategies that make urban living more sustainable. [9 marks]

• Adding equipment versus changing what people do by default
• A date and a figure for each scheme
• Which leg of the three-legged test each example stands or falls on