Are you visiting from outside your region? Visit your regional site for more relevant services and pricing.

Walkable communitiesJune 2008

Forget the car - hybrid or fully electric - why not develop communities where you can live and work by foot alone? David Bleicher argues for the comeback of walkable communities in the fight against climate change.

As you are visiting the BSRIA web site, you're probably involved in some capacity in the construction industry. If that's the case, you can't have helped but notice big changes over the last few years in the way we design, build and run buildings. Basically, we're waking up to the adverse effects that carbon dioxide emissions from buildings are having on the world's climate.

The UK Building Regulations demand that new buildings meet stringent emissions targets. Most planning authorities demand that on-site renewables cut emissions even further, and soon owners of buildings will have to advertise their energy efficiency to potential buyers and tenants. That will help us do something about the 60 percent of emissions that originate in buildings, but it doesn't mean we've got our built environment sorted out. Another 30 percent of UK CO2 emissions originate from the cars, trains and aircraft that we use to move around and between our towns and cities.

We know how to design buildings to be low-carbon. Put simply, we minimise the need to artificially light, heat, cool and ventilate the building, then we specify equipment that does so as efficiently as possible. But how do we design our towns and cities to be low-carbon? The answer is to reduce the distances we need to travel, and give preference to transport modes that use energy as efficiently as possible. I see three basic steps.

Three steps to sustainable cities
First, mix up the land uses. Put the places of work, flats, houses, shops, schools and so on near to one another. Town centres would still be predominantly commercial and the surrounding neighbourhoods predominantly residential, but you would no longer have the single-use districts typical of many of our towns and cities.

Second, increase density. In other words increase the ratio of useful floor area to developed land area. The principle is simple. If our towns and cities are denser, not only do we reduce pressure to build on green belt land, but we also reduce the distance we have to travel from, say, home to the gym. And if that distance becomes short enough, we'll be able to walk it or cycle it and not need to spend so much time at the gym in the first place. What's more, below a certain density, public transport is simply not viable.

It's all to do with having enough people within easy walking distance of a station or bus stop. I'm not talking about Hong-Kong style densities here. Walkability can be achieved with predominantly two to four-storey buildings. One thing is for sure, we'll never achieve walkability if our retailers continue to favour sprawling single-storey sheds with so much free parking that there's space even on Boxing Day.

All this mixing up of uses and increasing density won't help us at all if we continue to build our transport systems primarily around the needs of cars. You're not going to let your kids walk to school if there's nowhere safe to cross the road, and you're not going to give up driving unless you can get everywhere you need to go quickly and comfortably without a car. So the third ingredient in my recipe for walkable towns and cities is a solid public transport infrastructure.

The UK's track record
This is where a lot of British towns and cities get a thumbs down. Ever tried getting on a bus in Bracknell? Or getting from anywhere to Corby, Europe's biggest town without a train service?

Back in the 1970s, when it looked like the car would become king and public transport would melt to nothing, cities round the world found they could reverse the trend by building light rail systems. Since then, France has opened 17 systems. The USA, often thought of as a bastion of car-dependency, has also opened 17, adding to the seven cities that never ripped out their older tram systems.

In the same period, Britain has opened seven systems. If the 17 largest UK cities had light rail systems, you'd find yourself riding trams in places like Belfast and Hull.

The X-Factor
The fourth ingredient in the walkable recipe is a little harder for me to put my finger on. Let's call it je ne sais quoi. It's the X-Factor that makes a collection of buildings, streets, public spaces and geography more than the sum of their parts.

Maybe it's to do with regional styles of architecture and human-scale buildings. Maybe it has more to do with trees, water features and a hierarchy of private, semi-private and public spaces. It is hard to define but easy to spot. When parking your car at one of the many DIY warehouses that line London's arterial roads, you know it's not there.

For 5,000 years, we built walkable cities. It was only after the first world war, when cars became cheap and reliable, that we started to build at low densities, with land uses separated into zones. Visionary architects like Le Corbusier and Frank Lloyd Wright wrote about whole cities built this way. They looked great on paper, sketched as if viewed from an aeroplane, but places that got built along these lines turned out to be either windswept concrete jungles or sprawling car-dependent suburbs. The je ne sais quoi had been eradicated.

Planners today haven't quite figured how to get it back. Go to the historic centres of most of our towns and cities and you'll find a lot more people walking, cycling and using public transport than in the recently-built housing estates, office parks and retail complexes that surround the same towns and cities. It seems the more recently your corner of town was built, the more likely you are to do lots of driving. With the exception of a few urban regeneration schemes, most of what gets built today is low density, single use and car-dependent.

All of this, of course, is going to require a sea change in the way we think about planning. The function of city planners has evolved to cover the planning of road networks and the approval of new developments against codified sets of rules.

The effect of this is that the actual design work is carried out by property developers, who for the most part prefer to stick to whatever formula worked for them on the last 20 housing, office or retail developments. Today, there are no visionary planners. Or if there are I haven't met them.

Measuring walkability
So where does that leave building services engineers? For years we've been using tools like BREEAM to evaluate the carbon footprint of our building designs. But this only scratches the surface of the walkability problem. It's quite feasible to plonk a superstore down by a motorway interchange, miles from the nearest houses, and get a BREEAM excellent on account of a couple of bike racks at the side of the massive car park. We need a system that quantifies the carbon footprint of city plans and compares them with the alternative. And there always is an alternative.

So we need to develop an energy rating for cities. If we had one, we'd probably find that most new developments take the form of D-rated suburbs. In the absence of such a method, there is a simple test you can carry out yourself in your own neighbourhood. I call it the ice-lolly test.

Can a ten-year-old walk safely from your house to a shop, buy an ice-lolly, and get it home before it melts? If so, you probably live in a walkable community.

David Bleicher is a research engineer with BSRIA:

Tel: 01344 465600
or email