Cities Have to Be Car-Free in the Future, Say Experts

Just building cars is responsible for 4% of carbon dioxide emissions.

Miami rush hour
Rush Hour. B137/Wikimedia Commons

A University College London modeling report, published in "Open Science," looked at urban car use to conclude that cities have to become car-free to survive. Simply put, if we don't reduce the number of cars in our cities then they will just completely clog up and stop moving.

The study—"A paradox of traffic and extra cars in a city as a collective behaviour"—notes the number of cars is actually increasing faster than the number of people—in 2019, 80 million cars were built while the population increased by 78 million—and the manufacturing of those cars was responsible for 4% of global carbon dioxide emissions. That's bigger than aviation and almost as big as steel and concrete, and that's before you even fuel or charge them up.

The study authors construct a mathematical model where time is money, and residents chose between driving their car or taking public transit on the basis of the time it takes to do the trip. The paradox in the title is understood by most people who drive in cities: the more people who decide that driving is faster, the more crowded the roads, and the longer the trip takes.

"Where all individuals decide their commuting mode trying to minimize their costs, but the emergent result is the overall worst-case scenario, where the average commuting time is maximum and where all people decide to use their car," write the authors of the study.

costs increase when there are more cars
The economic cost of driving increases when there are more cars. University College London

The solution that any Treehugger would come up with is to build more transit or bike lanes and reduce traffic lanes and parking to get people out of cars; this would make it faster for everyone, even the drivers once it finds an equilibrium.

But this is hard to do when the majority drive, so most of the money goes guess where: "With an increased number of vehicles in the city, policymakers are inclined to construct even more car infrastructure and invest even more in private cars, which then creates more incentives for private vehicle use and results in even more congestion."

The car people are loud and getting louder these days in reaction to road calming, Low Traffic Networks (LTNs) bike lanes, and any other moves that might make their trip a few minutes longer. The study authors note that there are many reasons that the car ends up dominating the picture:

"The rapid growth of urban population, land-use policies and car-oriented infrastructure that dominated the twentieth century derived in sprawling low-dense suburban areas, increasing the commuting distance at the expense of active modes of transportation (walking and cycling), and making it economically costly to introduce efficient public transport with high frequency and reachable at short walking distance. The car became the preferred mode of transportation for many city-dwellers, increasing the number of motorized trips and, as a consequence, augmenting the congestion and air pollution."

Bailouts, subsidies, tax breaks, and "unethical industry efforts to hide the negative environmental and health impacts of car use" all hide the real economic cost of cars. So it's hard to make a rational choice between transit and driving, and more people drive, and that's a problem.

"Mobility is a crucial aspect to consider both for urban studies and for sustainability. Producing cars takes 4% of the total carbon dioxide emissions, but there are all types of other costs related to motorized mobility. These include direct costs, such as the petrol or electricity they consume, infrastructure and congestion itself, and indirect ones, including road insecurity, the (un)active mobility, the space devoted to cars in cities and others."

Alternatives have to be actively promoted, with more travel options, plus local shops and services. Also, "increasing the induced costs that car users put on themselves and that public transport users put on drivers could be achieved with some interventions, by reducing the space devoted to cars, with more public transport lanes, tramways, wider sidewalks, and pedestrian roads, for example."

Their model basically concludes that to make transit and active transport more attractive and appealing, one has to make driving less appealing. This is a tough sell, especially in a report coming from London, where there are incredible battles over every effort to calm streets and reduce traffic. It's got to the point where the drivists claim they actually represent disabled people who have to drive, businesses who need customers who drive, and poor people, who have to breathe their exhaust. It's all upside down.

In the press release, the report author Dr. Humberto González Ramírez (Université Gustave Eiffel) said: "Currently, much of the land in cities is dedicated to cars. If our goal is to have more liveable and sustainable cities, then we must take part of this land and allocate it to alternative modes of transportation: walking, cycling and public transport."

The study authors say their model can be applied to any city, but everyone already knows the results intuitively: when you add more cars, you get more congestion.

View Article Sources
  1. Prieto Curiel, Rafael, et al. "A Paradox of Traffic and Extra Cars in a City as a Collective Behaviour." Royal Society Open Science, vol. 8, no. 6, 2021, p. 201808, doi:10.1098/rsos.201808