You cannot reduce traffic jams by building more lanes — in fact, more lanes often create more traffic. But new studies show that reducing roads doesn't make traffic worse.
For instance, Paris in recent decades has had a persistent policy to dramatically downsize and reduce roadways. "Driving in Paris was bad before," said Duranton. "It's just as bad, but it's not much worse."
So where did those other drivers go? Many of them switched to public transit, which in Paris has increased by 20 percent in the last two decades. Other trips have simply been avoided, or done on foot. It's not just Europeans who are eager to get out of their cars. San Francisco removed a highway section, called the Central Freeway, that carried nearly 100,000 cars per day in 1989. The boulevard that replaced it now only carries around 45,000 daily cars and yet they move. (Yes, I've been stuck in traffic on Octavia Boulevard, but it's not like you never get through.) Perhaps the biggest success story has been in Seoul, South Korea, where the city tore down a highway that was considered a vital roadway corridor, carrying 168,000 cars per day. After replacing the cars with a river, parkland, and some smaller roads, traffic didn't get worse and many other things, including pollution, got better.
At Wired, Adam Mann goes on to explain that there are limits and caveats to this trick, but that, despite this, it does remain a great example of how what actually happens in the real world does not necessarily conform to our "common sense" expectations of what should happen in the real world.