Officials in major U.S. cities are looking for a way to carve out some control over the development of self-driving vehicles, by regulating the curb space where fleets of autonomous cars are likely to drop off and pick up passengers and packages.

Curbs already have become conflict zones in cities as more kinds of vehicles—from Ubers to Amazon delivery trucks to buses to bikes—jostle for access. That competition is likely to intensify when autonomous cars hit the road in dense urban areas, spurring some transportation officials in large U.S. cities to prepare for big changes. The moves have big implications for ride-hailing firms like Uber and Lyft, whose business model is based on free access to road and curb space, and for the companies who are working on autonomous vehicles, including Alphabet and Detroit’s automakers.