Study: Without Fewer Cars, Cities Will be 'Overrun by Gridlock'

"Understanding how cars affect cities and commute times is of vital importance, both for the sake of the climate—transportation is the biggest share of U.S. emissions and a growing chunk globally—and quality of life," writes Dharna Noor. A new study "modeled the time car trips take, factoring in the baseline length of the trip on empty streets, the time added by other drivers who create traffic, and the time added by the designation of some street lanes for exclusive use by pedestrians, buses, and bikes" to conclude that "we have to start getting cars off the road—and fast—if we want to avoid cities being overrun by gridlock."

The choice between driving and using other modes of transit, Noor writes, "creates an inherent paradox. If more people decide that driving is quicker, there will be more traffic, clogging streets and making trips longer. The longest trips across town, the authors found, were the ones taken when every single resident tries to reduce their commute times by driving, thus creating the most traffic." 

"The authors also discuss some ways to reduce the time it takes to get across a city and lower carbon pollution, including investing in more reliable and quick public transit, building more bike lanes and walking paths, and not separating residential areas from commerce. They also suggest reducing the number of traffic lanes in cities and building less parking to discourage people from driving or even owning a car in the first place, making city travel faster for everyone."

Despite some limitations in the analysis, "the model is instructive, showing the logical fallacy of attempting to reduce drive times by increasing the use of cars."