The economic cost of traffic congestion in cities is significant. The Canadian Taxpayer Alliance for example states that in Toronto the cost of traffic amounts to more than one and a half billion dollars per year in lost productivity (not to mention additional consumption of greenhouse gases and resulting pollution and smog from inefficiently operated vehicles – which also bear economic costs).
One way to address traffic congestion is to provide a bypass for vehicles around city traffic machinations. A ring road, by definition, is to serve as exactly that. If there’s congestion on city roads, a ring road will provide an alternate route for traffic to circumnavigate the city.
But definitions can differ from reality. Does a ring road act as an orbital around the city? If there is urban development beyond it, by definition, it is not a ring road. If the road acts to increase capacity in the transportation network – building more roads to provide additional route choice to reducing traffic – then it is less a ring road and simply additional urban road infrastructure. However, increasing road supply does not equate to traffic alleviation.
I’ve written previously about the supply and demand model of traffic management. In brief, traffic is a function of demand. Too much demand exhausts the resource, in this case, roads. More resource is thus produced to accommodate demand; demand meets supply; repeat. More roads equal more traffic. In this case, a ring road produces more traffic. Or as expressed through a city planning model, a ring road – by adding more road capacity to the vehicular transportation network – allows the perpetuation of auto-centric planning.
Tim Miller writes in China’s Urban Billion, that ring roads allow the increase of “potential area for urban development in one stroke, as all land within an orbital will quickly become fair game for development.” Citing the World Bank, Miller continues, “What’s the best way to take land? … You draw a circle around the city and call it a ring road. It’s the most efficient way of circumscribing rural land. This means you have all the incentives for urban sprawl.” Anecdotally, Mr. Miller notes Beijing has five ring roads.
A demand for roads can be tied to the design of a community. Seeking efficiencies in a system designed for automobiles through the provision of additional road capacity does not resolve the underlying issue. If traffic congestion is to be ameliorated, supply shouldn’t be addressed. Address demand. By focusing on supply (i.e. building more roads), and not demand (i.e. augmenting a city to lessen vehicular demand), the production of an auto-centric city continues.
To ensconce my tongue deeply in my cheek, as city historian Lewis Mumford said, “Forget the damned motor car and build the cities for lovers and friends.”
Editor's Note: This post was revised on 11/15/2013