We know that Boris Johnson’s fantasy of “smoothing traffic flow” will act as an incentive for people to get into their cars and, even more so, for businesses to move more stuff around. In a city like London there is much more potential demand for road space than could ever be supplied, because individuals and businesses who see an empty bit of road will always conjure some reason to fill it. An equilibrium is maintained by the tolerance that individuals have for sitting in traffic and the tolerance that businesses have for spending money doing business on the roads. Add or remove capacity to London’s road network and it will not make the slightest difference to congestion or journey times. It’s not like we haven’t tried it enough time to be sure of that.
What is not so obvious is that in addition to pulling people into motor vehicles, it will push them in too. There are several reasons why. One of them is that the mayor is ripping out traffic lights and pedestrian crossings, making walking more difficult, dangerous, and time consuming. There are a number of reasons why this will push people into cars, but I stumbled upon a nice one while skimming through Hume et al, Walking and cycling to school: predictors of increases among children and adolescents.
Hume et al looked at the variables that affected the success of a programme to encourage walking and cycling to school. They surveyed the opinions of the children and their parents on all sorts of aspects of their lifestyles and of their social and physical environments. Two variables were strongly associated with success: the perception that other children in the neighbourhood were walking to school*, and the provision of safe crossings.
Well, not exactly the provision of safe crossings, but the perceived provision of safe crossings. Specifically, the survey asked participants if they agree/disagree with the statements “there are no traffic lights / pedestrian crossings for my child to use” and “I am satisfied with the pedestrian crossings in my neighbourhood”. Parents, whose job it is to worry, are of course easily affected by perceptions of safety, and when they perceive safety to be compromised they do something about it — like put their child inside a big metal box.
Even if there is just about a sufficient provision of crossings to get their child to school, the provision of crossings in the wider neighbourhood will still affect whether a child is walked or driven to school for all sorts of reasons, including: the perception of how safe it is to walk to school is influenced by an environment wider than just the route to school; the number of other children in the neighbourhood walking to school will itself be influenced; and those living in less walkable neighbourhoods are more likely to own and frequently use cars, including over short distances, making driving to school seem like a less unusual thing to do.
Off course, none of this says anything certain about what the precise effects of the mayor’s removal of traffic lights and pedestrian crossings will be — quite the opposite. In the complex, chaotic, unstable and irrational world of travel choices, the mayor can’t hope to make isolated quick fix tweaks without sending unpredictable shocks through the system.
Further problems with the mayor’s traffic lights games are discussed by Cycle of Futility.