In the email, unearthed from a company report by the San Diego Union-Tribune, Ace Parking CEO John Baumgardner says that demand for parking at hotels in San Diego has dropped by 5 to 10%, while restaurant valet demand is down 25%. The biggest drop, unsurprisingly, has been at nightclubs, where demand for valet parking has dropped a whopping 50%.

The numbers appear to be estimates, and Baumgardner doesn’t describe a timeframe for the declines. The assessment, written in September of last year, is also limited to San Diego, though an Ace Parking executive told the Union-Tribune that it has seen “similar” declines at its 750 parking operations around the United States. The company is focused on using technology, including better parking scheduling and booking options, to remain healthy.

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But much more is at stake than the revenues of the parking business – cities stand to benefit immensely as demand for parking drops. Parking spaces and lots generate relatively little tax revenue or economic activity relative to commercial operations, and by increasing sprawl may actually harm the economy of cities like Los Angeles.

Even back in 2015, cities were already relaxing zoning requirements that set minimum parking allotments, and there are now even more signs that city planners are thinking differently about parking. Perhaps most dramatically, a new Major League Soccer stadium being planned for David Beckham’s Miami expansion team may include no new parking at all – but will have designated pickup zones for Uber and Lyft.

The decline of parking will only be accelerated if and when autonomous vehicles become widespread. That sea-change which will make it easier to locate parking at a distance from urban destinations, and could further reduce car ownership. That will be bad news for the Ace Parkings of the world – but everyone else should welcome the decline of the urban parking lot.