The north-south divide of green belts
This piece originally appeared in CityMetric in 2017. The economics of supply and demand is a fickle friend to urban planners everywhere. Say you work in a city with traffic jams, and the council decides to increase road capacity. In the short run, productivity improves, as getting about the city becomes easier. But in the long run, the demand for roads increases as travelling by car becomes a more viable option for an increased number of commuters. Previously, these commuters might have taken public transport, or chosen not to travel. However, now that road capacity is greater, they are compelled to drive. This results in a return to the status quo of traffic jams, just on bigger roads. This phenomenon is ubiquitous in American cities such as Los Angeles, where public transport plays second fiddle to private. The same is true for housing. When demand for housing is high, but supply is low, common sense would dictate that housing supply ought to be increased in the areas where demand i