A striking aspect of the NPPF impact assessment is its striking ignorance of 30 years of research and evidence of the advantages of smart growth over sprawl. To my mind this made the whole impact statement baseless, out of date and showed an ideological bias rather than evidence of keeping currently with the latest thinking in urban and transport economics.
One key thinker is this field is Matthew Turner of the University of Toronto. Recently he has been gaining attention with research on traffic congestion in the US showing the ‘universal law’ first posed over 40 years ago that building roads for commuting leads to them simply being filled up with congestion, to be true. More controversially he suggests that increasing public transport capacity doesn’t help either as this just leads to more capacity on roads being freed which then fills up. To my mind this is nothing new in the English Literature as the late Martin Mogridge had the same theory 20 years ago in Jam Today Jam Tomorrow, but Modgridge made the conceptual leap that Turner hasnt that public transport increases the maximum employment density of cities and so rises urban land values. Both Mogridge and Turner have the same solution – congestion charging, and Mogeridge was the key theorist who influenced the case for congestion charging in London by suggesting that if the funding were spent on public transport it would have positive welfare benefits in raising urban capacity and land prices.
I wanted here though to highlight an earlier paper by Turner that should be essential reading for the rather ill informed treasury economists influencing the NPPF.
In A Simple Theory of Smart Growth and Sprawl 2006 he argues that high density housing within walking distance of a store is welfare preferable to a low density car orientated scheme at a city edge, even though individual consumers and developers may have a low density preference. The simple idea, although the paper will be unreadable to those without an economics background, is that these individual decisions dont take into account the benefits to land value of the shop developers, whilst the presence of the high density housing aids the viability of the store.
What this and similar research indicates is that there is considerable welfare advantages in developing housing in large doses where housing, public transport and retail can be planned together. Smart growth is not just high density housing it is strategic planning making decisions which make compact communities workable.