His earlier work led to passage in 1992 of California's parking cash-out law, which requires many employers who offer free parking at work to offer commuters the option to take the cash value of a free parking space in exchange for not using a space.
In 1997, Shoup studied eight employers in the L.A. area and found that cash-out programs reduced solo driving to work by 17%. Transit use increased by 50% and carpooling increased by 64%. A bill now in Congress would extend California's requirement nationwide.
Not everyone subscribes to Shoup's theories. He recently sparred online with Randal O'Toole, a senior fellow at the libertarian Cato Institute known for his website, The Antiplanner, dedicated to "the sunset of government planning."
"I am an economist, and as long as Dr. Shoup is thinking like an economist … our thinking coincides," O'Toole wrote in an e-mail. "It is when he starts thinking like an urban planner, trying to change people's behavior and in particular trying to reduce driving, that we have a problem. … Mobility is valuable, and any limits placed upon it harm people and the economy."
Shoup depends on his bicycle for much of his mobility. He freely confesses, however, that when behind the wheel of his silver 1994 Infiniti J30, he often circles the block looking for a free parking space. "I don't like paying for parking," he says with a shrug. "But free parking is ultimately not beneficial."
It's the conclusion more planners are reaching.
"There's a sense in a lot of places that parking policy has gone disastrously wrong," said Patrick Siegman, a principal with NelsonNygaard Consulting Associates, a transportation planning firm in San Francisco. "As people think about it from scratch again, they're realizing that a lot of old ideas have been a huge failure."
Shoup considers Siegman the first Shoupista.
He was a student at Stanford circa 1992 when he first discovered Shoup's monographs in the Green Library stacks. "Because of that experience, I decided to become an economics major, and wrote my undergraduate honors thesis on the economics of parking," Siegman said. "When I graduated in 1994, I became a transportation planner and started trying to put his principles into practice."
At a recent meeting of the Glendale Transportation and Parking Commission, Bonnie Nelson, a co-founder of NelsonNygaard, followed Shoup as speaker and cited him chapter and verse.
"Don is treated in some places like Einstein, like he has discovered the theory of relativity," Nelson said.
In Shoup's view, Old Pasadena and Westwood Village illustrate the effects of different parking policies. In 1993, Old Pasadena installed $1-an-hour meters and began using the revenue to spruce things up. Many area employees who had parked on the street and moved their vehicles every two hours began to pay for parking in city structures, so that curb spaces were freed for customers. The shift helped transform the area from a blighted eyesore into a vibrant destination with shops and restaurants. Shoup doesn't take credit for Old Pasadena's change, but he often uses the area as Exhibit A in his talks.
That same year, Shoup said, merchants in Westwood petitioned the city to cut meter rates from $1 an hour to 50 cents. Curb parking was underpriced and overcrowded, and the meter money flowed into the city's general fund rather than back to the area. Today, Westwood Village residents and merchants bemoan the cracked, trash-strewn sidewalks, neglected landscaping and numerous vacancies.
To Shoup, the matter comes down to a simple question: "Would you rather have free parking and dirty sidewalks or paid parking and clean sidewalks?"