Last week, America’s “parking guru” Donald Shoup announced his retirement from UCLA’s Luskin School of Public Affairs. After 41 years of teaching at the university, the urban planning prof will end his post on June 30th.

Shoup is best known for his ideas on parking policy, and he’s a man urbanist wonks love to quote. His seminal book, The High Cost of Free Parking, is considered a must-read among urban planners and policymakers.

Janette Sadik-Kahn just name-dropped @UCLALuskin’s “parking godfather” Donald Shoup and he’s here! #HammerLive pic.twitter.com/bL1jY3cx2s

— topomodesto (@topomodesto) March 27, 2015

“It’s unfair to have cities where parking is free for cars and housing is expensive for people.” — Donald Shoup, parking expert #CityLab2014

— Jim Dalrymple II (@JimDalrympleII) September 29, 2014

Alan Altshuler, professor of urban planning at the Harvard Kennedy School of Government, wrote on the Luskin School’s website:

“Don is probably the most creative, original planning scholar who has been at work during the past several decades. There may be another U.S. planner who has combined path-breaking research, profound analysis and practical impact in such distinguished fashion, but I cannot think of who that might be.”

The question is now: Who will mainstream media call when they need a quote for a parking story? In the last month alone, Shoup was the go-to source for many articles on the challenges of fitting cars into dense cities. The Boston Globe asked him about the trouble with transit station parking lots filling up and preventing later morning commuters from riding.

In an article on relaxing parking penalties in the U.K., the Economist cited Shoup’s argument for more common-sense parking fees: “Donald Shoup … argues that parking should be priced so that some 15% of spaces are vacant: fees should rise and fall with demand. That would cut down on cruising for parking spaces, which Mr. Shoup estimates accounts for around 30% of all cars in congested traffic.”

And for a piece on how complete streets planning is reducing the amount of street parking in U.S. cities, Shoup told USA Today, “the cause of most of the outcry over lost parking spaces is a simple resistance to change.”