When Greg Rogers left his gig as a Washington, DC, lobbyist in 2015, he did what any savvy, mid-20s kid with a car and a light wallet might: He signed up to drive for a couple of ridehailing services. “Living the millennial dream means quitting your job, driving for Uber and Lyft, and trying to figure it out,” he says.

He was a menace. “It was always the same dance,” says Rogers, now a policy analyst with the Eno Center for Transportation, a think tank. “I wouldn’t be able to see the passengers, and couldn’t find a place to park safely. So I did what a lot of Uber drivers did: I threw on the hazard lights and blocked a lane.” He and his fellow drivers stopped traffic, risking tickets and sparking jams along the way.

Rogers and his compatriots were just foot soldiers in an unending war of conquest that rages in nearly every city in the country, even the world. The battleground is ubiquitous but rarely merits a second look. In some places, it occupies mere inches of space. But the territory is now fertile soil, its coveters many. We are talking, of course, about the curb.

The curbside has always been a a place for walking and loitering. But in just the past decade, smartphone technology has enabled new transportation services, all of them looking for their own bit of the terrain. The curb is home to bike share programs and the cycling lanes that help their users get around safely. It’s a spot to pick up and drop off passengers (Uber, Lyft, Chariot, Via, public buses and streetcars, paratransit) and things (UPS, FedEx, Instacart, Postmates). Some cities have set aside space for carshare services (Zipcar, Maven), or scooter-shares (Scoot). Others have found new and creative ways to charge for parking spots, experimenting with tech that adjusts prices based on demand.

“Cities have started to rethink how their streets are designed from curb from curb,” says Matthew Roe, who directs street design initiatives for the National Association of City Transportation Officials and authored a new curbside management white paper released this week. “They’ve started to realize they need more tools to manage that valuable curbside space. It’s the most valuable space that a city owns and one of the most underutilized.”

What you do with the curb sets the tone for your whole city. And through this grey chunk of concrete, local governments are starting to communicate how they'll handle their entire transportation systems. Favor a system that asks citizens to share resources, by making room for, say a bikeshare program, and you say one thing. Favor private parking for residents, and you declare war: “When I think about curb, the first thing that comes to mind is how people react when you take away parking,” said Sarah Jones, the planning director for the San Francisco Municipal Transportation Agency. She was speaking at a surprisingly lively event about curbs, hosted by the San Francisco Bay Area research and advocacy organization SPUR this month. Residents complain, Jones said, of private interests taking over the space, but they don't seem to get that this is exactly what's been happening all along. “I’m not sure what is privatizing public space more than storing your vehicle in it," she said.

Good thing American cities are getting a little loosey-goosey with curb control, experimenting with policies that just might make the places more livable, for everyone.

Space Wars

Rogers, the driver-turned analyst, was inspired by his struggles to come up with a new curbside management concept, one that Washington and other cities are beginning to take very seriously. He calls it “shared use mobility zones,” and you can think of it as flex-space: At certain times of day, the city reserves the curb for specific functions. During rush hour, maybe, it’s a pick up stop for a microtransit service. In the afternoon, it’s a spot where trucks can pull over and drag in deliveries without double parking. At night, it’s a designated point where a for-hire car can meet passengers pouring out of the bar on the corner. “The best part is that cities can adjust based on what their goals are,” says Rogers.