America is built around cars. And most of us expect that we’ll be able to park our cars for free, pretty much anywhere we go.

But economist Donald Shoup of UCLA has made a name for himself by advocating an alternative scheme: charging for street parking anywhere there are more people with cars than spaces to park.

Shoup’s 2005 book, The High Cost of Free Parking, articulated why exactly he thinks free parking is such a bad idea. His ideas have started to influence policy: several cities, including San Francisco, have recently begun experimenting with the variable, market-set pricing scheme he thinks makes the most sense. And recent studies have confirmed that it cuts down on cruising time and traffic congestion.