The scarcest resource for motorists is time. You have to get to your destination at great speed. The scarcest resource for communities is space. You have to crowd in thousands in one place. However, time and space, at least in urban mobility, are not exactly friends.
And if the spirit of the times in the city is to reduce the space devoted to automobiles, there is a simple reason for that: studies show that it is currently the best way to make mobility more fluid in the great majority of cases. This can be explained by a simple phenomenon. Let’s call this the elasticity of automobile traffic.
Researchers have known for years that by adding roads, authorities do not alleviate traffic. They increase the desire to travel alone. This is called induced traffic: the more roads there are, the more cars there are and the more traffic congestion there is.
The opposite is also true: if we close roads, there will be fewer motorists and, quite quickly, less road congestion as well. This is called circulation evaporation.
The Barcelona example
Barcelona has been proving for five years that traffic evaporation is possible for just about every city. The Catalan metropolis said it had the highest automobile density in Europe five years ago. She decided to tackle this by creating what she calls “superneighborhoods”. Its premise: if we reduce the number of roads reserved for cars, the problems linked to road traffic will evaporate.
A bit like Montreal, the center of Barcelona is crisscrossed by roads that intersect at right angles (except Diagonal Avenue and a few others). We therefore grouped blocks from nine adjacent neighborhoods into a dozen superneighborhoods. The speed limit is 30 km/h. The City has also eliminated almost 10,000 on-street parking spaces. We replaced them with 245 km of cycle paths, lots of greenery, and we removed the fences around 200 schoolyards so that children could have fun even in the street.
We are beginning to know the impact of these measures. And it seems positive. Between 2017 and 2022, car traffic fell by 15% in this part of the city. The number of registered vehicles also fell by more than 10%. Accidents and interventions by emergency services have also decreased.
It’s not a revolution, but Barcelona believes it has found a better balance between space and time that satisfies more people. Business owners who thought their business was threatened by the lack of parking saw their customers visiting them by bike. Local commerce is not a myth.
It should still be remembered that Barcelona, worthy of European cities, has a public transport network that is much more efficient and accessible than that of a city like Montreal.
The Downs-Thomson paradox
The City of Montreal could have cited the example of Barcelona to explain its decision to close the Camillien-Houde route. There are others. When we read the academics who look at solutions to relieve congestion on road networks, we realize that Quebec suffers from a syndrome that has a name: the Downs-Thomson paradox.
According to this paradox, contrary to what one might believe, any creation of new road infrastructure has the effect of causing more congestion, in particular due to induced traffic and another phenomenon that could be called “consumption of water”. ‘space-time’ of automobiles.
In other words, a car needs more space as its speed increases: the distance separating it from other vehicles, other lanes, other road users and even street furniture is exponentially greater as it increases. the vehicle goes fast.
Logically, the more cars there are or the more space is limited, the less people can move quickly. Busy or distracted motorists often tend to overlook this detail. This causes many problems, including accidents. And a lot of discontent.
All this was summarized superbly five years ago by two researchers from the University of Lyon, Yves Crozet and Aurélie Mercier. “Faced with complaints from motorists who criticize the time lost in traffic jams, public decision-makers consider that congestion results from insufficient roads. It therefore seems logical to them to embark on road widening or extension projects. »
“However, it should be borne in mind that this may result in an increase and not a reduction in congestion. »
Done well, the researchers conclude, a strategy to reduce road infrastructure could reduce congestion, the need for road surveillance and the size of the vehicle fleet.