Enrique Peñalosa, one of a succession of mayors who transformed the Colombian capital Bogota in the 1990s, spoke in London this month with a lesson on the mathematics of democracy. It began with some simple equations: in a democracy, every man, woman and child is equal. For Peñalosa, this endows everyone with an equal right to the public spaces of the city. A child with a tricycle has just as much right to use the streets as a car with one person in it. And a bus with one hundred passengers has one hundred times more right to road space than that same car.
This is the kind of rhetoric Peñalosa is famous for, but it is also the kind of elegant argument that can shift ground in politics, and can ultimately be used to build legal challenges to unjust policies. This is partly his intention — these equations are robust enough that a city's population can use them to demand real change in how our streets and roads are designed.
Indeed, it is the kind of argument gaining traction in court rooms, as the American planner Ed Soja describes in his recent book, Seeking Spatial Justice. The Los Angeles Bus Riders Union successfully sued the Metropolitan Transit Authority, presenting spatial analysis that forced it to reorient its bus network towards poorer areas of the city. It will be short work for a talented legal mind to force authorities to reorient precious street width towards pedestrians and cyclists using similar spatial arguments.
It will also be a way of thinking to focus the minds of policymakers during increasing resource scarcity. Peñalosa asks, "if there was fuel for only five per cent of vehicles, would you allocate it to cars or to buses? If there was road space for only five per cent of vehicles, to whom would you give this space?" Rather than spend money on expensive highways and rail projects in a bid to mimic more 'developed' cities, Peñalosa established low-cost bus corridors, using the money saved to build schools, nurseries and libraries throughout the city. Where Japanese transport engineers (brought in by JICA, Japan's international cooperation agency) proposed an eight-lane highway, Peñalosa built a 30-kilometre greenway. "These are the things you can do if you don't invest all your money in roads."
Peñalosa envisions cities where the vast majority of commuting consists of people walking on pleasant sidewalks, cycling on spacious bike lanes, and buses rolling unencumbered at speed along dedicated corridors. Cars will continue to play a part, I imagine, in the distribution of goods and other special journeys; it will be so restricted spatially and financially that only those with strong economic reasons for driving will afford to do so, but there will also be so little traffic that they will have little to complain about.
One might be tempted to seek a technical solution, deriving some optimum balance of footpath and cycleway, bus lane and road. But Peñalosa is quick to argue that no such equilibrium exists. "There is no 'natural' level of car use in a city. The more roads, the more cars." He repeats himself to an unseen audience of urban elites. "I wish developing-country cities would understand: traffic is not caused by the number of cars; it's caused by the number of roads."
The science is behind Peñalosa on this point. Congested cities constantly dream that they can build highways to alleviate their traffic problems, but with each new road comes increased congestion that surpasses the engineers' predictions. The UK's Standing Advisory Committee for Trunk Road Assessment (SACTRA) tried to settle the matter by analysing traffic growth after building the M25 ring road around London. To many engineers' surprise, the SACTRA and other studies concluded that not only does expanded road capacity increase traffic over and above the additional road space, but it adds congestion even to parallel routes that authorities hoped to relieve. Car commuters perceive the additional time gained as an opportunity to take longer trips and travel further in and out of town, increasing their car dependency. This is a phenomenon known as induced traffic — each new road induces a slightly disproportionate increase in traffic throughout the road system around it.
As Peñalosa declares, "the amount of roads is a political decision, not a technical decision." He asks, why do the Netherlands have more bikes than Spain and Italy, when the weather is so much nicer in the Mediterranean? His answer is contentious, but his meaning is clear: "it's because Spain and Italy are less egalitarian societies", that is, they make the political choice to favour car users over those dependent on cheaper modes of transit.
Thinking of road space as a technical problem also misses the point about the politics of footpaths. Improving our footpaths and bike lanes is not simply to improve the commuter experience for pedestrians and cyclists; it is to enable a more democratic way of life. The rich man may use streets for little more than driving between meetings, but he can afford to since he enjoys a beautiful lifestyle in the confines of his own home.
But for many poor people, one's own home can be small, restrictive, a reminder of one's low status. For many, the ability to enjoy simply being in dignified spaces, to feel dignified oneself, comes only through the enjoyment of public space. Providing such spaces, from the footpath outside the home of every resident, to our busiest commercial thoroughfares, is one of the most empowering political acts a city can offer its people, all its people, equally.
Peñalosa insists that the footpath is not the slower cousin of the roadway, but the linear sibling of the public square — a place to watch people, meet, talk, pass time without being forced to spend money, read the public mood and participate in local happenings. Freeing the width of the street from cars does not simply enable pedestrians to commute more easily but allows all these democratising activities to flourish.
Peñalosa offers a yardstick for policy taken from that other prophet of civic-minded urbanism, Danish architect Jan Gehl. "A good city is one where people want to be outside in public space." Every initiative of urban design and transport can be evaluated by the simple questions, "does it make the city more or less pleasant to walk?" It is a great pleasure that Peñalosa takes the time to tour the world's cities, to walk us through these basic principles of equality and democracy.