Over the last few months, I’ve spent a lot of time looking at century-old images of U.S. streets. There’s a window of a dozen or so years at the beginning of the 20th century, at the dawn of the automobile age, where American cities were remarkably multimodal—including a wide range of small personal vehicles.

Take, for example, “A trip down Market Street before the fire,” a film of downtown San Francisco from the era before the 1906 earthquake—and subsequent fire—leveled the city.

About a minute in, a man exits the cable car with a baby and walks, with confidence, across several lanes of traffic navigated by several types of vehicles—propelled by human, horse, and motor—glancing only briefly at the oncoming cable car on which the camera is positioned.

People of all ages and abilities, sharing the roadway, moving at human speeds, negotiating around the sometimes erratic paths of other vehicles. When I was reporting a story about urban transportation one year ago, I envisioned future streets that were much like those streets of a century ago, where the wide expanses between our buildings would offer places to explore more options beyond cars.

Everything old is new again. pic.twitter.com/97Ft4Db38h — Autonomous Law (@SafeSelfDrive) April 21, 2018

Little did I know the future was arriving much faster than I envisioned.

As noted by Jim McPherson, a lawyer focused on transportation technology, what we’re experiencing now is actually the country’s second micromobility revolution. Electric bikes and motorized scooters were plentiful on U.S. streets a century ago. But like so many transportation innovations, they were muscled out by cities that promoted the perceived freedom of cars.

Now, with the growing number of cars in U.S. cities and growing vehicular emissions, motorized bikes and scooters are tantalizing, especially since the average speeds on congested urban streets are less than 10 mph.

Micromobility has become the “holy grail” of transportation, says McPherson. “It is personal, can be sustainably powered, and also solves the urban geometry problem.”

Still, it was hard for me to envision how our new fleets of motorized vehicles—and the challenges they have presented—might fit into our contemporary, car-centric streets. Until I saw photos of San Francisco’s Market Street, of all places, taken by Sergio Ruiz over the last few months. It’s striking to see how many modes of transportation are captured in a single photo, including, of course, electric scooters.

I want to point out two things about this particular image. Shared dockless scooters are not on San Francisco’s streets right now. They’ve been ordered off pending a permit review. But this scooter isn’t a dockless rental, it’s someone’s personal Razor scooter, meaning people are using these to get around cities whether or not a startup is depositing them on their corner. Secondly, the street itself has been designed to accommodate many modes comfortably with a designated 10-mph zone, where, at any given moment, you might encounter a bike, scooter, or skateboard—or the motorized counterparts of each.

Market Street offers a glimpse of how contemporary U.S. cities might be edging towards that shared-street mentality (a proposal to completely ban private cars from the street was ahead of its time). But it also illustrates something else—if you give people ample space to move at a safe speed using the mode of their choice, anyone can use the street.

All over the country, city leaders are spending their summers devoting careful thought to the number of rentable e-bikes that can be deployed on streets at once, where electric scooters might be parked, and how dockless companies should be punished for violating these terms. Just this week, the National Association of City Transportation Officials, which collates best practices from its 62 member cities, released draft guidelines around the regulation of “small vehicles.”

Yet largely absent from these decisions—at least the public-facing ones—are how cities plan to quickly and dramatically reconfigure their streets to allow people to actually use anything but a car.

It’s not like cities haven’t seen this coming. Traditional bike share has seen rapid growth nationwide—ridership in 2017 was up 25 percent over the previous year.

Now, with Uber adding Jump electric bikes and Lime scooters to its app, and Lyft buying the country’s biggest bike-share operator, Motivate, and launching its own Lyft Bikes, the landscape is changing much more rapidly.

Cities say they aren’t sure if scooter trips are replacing car trips. But how can cities make sure that scooter trips are replacing car trips?

By the end of this year, renting bikes and scooters will be a mainstream transportation option readily available to tens of millions of people in over 100 U.S. cities with the tap of a finger—and offered as part of trip-planning itineraries that include bus, rail, and ride-hailing.

The need for safety infrastructure was already urgent—but it’s especially urgent now. The U.S. streets that have not adequately planned for bikes for decades—most of them—will soon welcome even more types of wheeled vehicles. And the sidewalk—which has become the flashpoint in these conversations—is already far too narrow and poorly maintained in most cities to accommodate the needs of most walkers, let alone scooter operators afraid to ride in the street.

Whether the vehicle is docked, locked, electric, pedaled, shared, or owned, there is clearly a growing group of Americans who want to use their streets in a new way, right now. Cities have spent years chastising Uber and Lyft for increasing congestion. Now these companies are proposing solutions to get their users out of cars—and cities need to work quickly on the necessary changes to make this new urban geometry work.

While the conversation around dockless transportation has mostly been about sidewalks and curbs, there is a far bigger decision at stake here—cities must decide right now what kind of transportation they want to prioritize.

Cities say they aren’t sure, for example, if scooter trips are replacing car trips. But how can cities make sure that scooter trips are replacing car trips?

“We’ve really seen that first and foremost cities need to be thinking about nimble policies and nimble strategies—that’s hard to do in transportation planning,” says Jean Crowther, senior associate and new mobility group lead at the Portland, Oregon-based Alta Planning + Design, Inc. But some planners are trying to design more flexible streets, she says, by using data and metrics to establish hierarchies when it comes to funding, resources, or, perhaps most crucially in this conversation, space.

Now, instead of the previous goal of prioritizing the movement of one mode (cars), streets can allocate space based on improving health, equity, safety, or access to school and jobs—regardless of whatever new modes are introduced, says Crowther. “While we have these trends that are important and fast-moving, the goals will generally not change.” Some cities, for example, are piloting “fossil-fuel-free streets” where achieving zero emissions is the goal, meaning walking and biking would be prioritized over everything else.

Cities need to design for the modes they want people to use because they already lost the opportunity once, says McPherson. In the 1890s, American cities experienced a bicycle boom so pervasive it changed women’s fashion. Bikes were such a popular mode of urban transportation that cities scrambled to build cycling superhighways for them. Yet bikes lost that valuable urban real estate as sprawling cities prioritized cars.

With shared mobility companies providing a wide range of multimodal offerings themselves, McPherson thinks there’s an opportunity for bike advocates to merge with the momentum behind other non-car vehicles and all take the lane together. “Human-powered bikes got shoved onto the sidewalk and have been fighting to share street space ever since,” he says. “Now they just might get it.”

We’re already seeing how riders of new modes are becoming advocates for the safety infrastructure that these cities desperately need.

In Santa Monica, California, where the number of dockless scooters are capped by a 16-month feasibility study, Bird has added an option where local riders can dispatch an email to the city’s representatives expressing their support for scooters. A Santa Monica spokesperson confirmed that city leaders had received about 1,000 emails.

The tactic takes a page from Uber’s early efforts to turn riders into advocates for ride-hailing regulation in their cities, and has even been nicknamed “Travis’s Law” after Uber founder Travis Kalanick. (Another ex-Uber employee named Travis VanderZanden founded Bird, so I guess it holds up.)

But Bird has also included advocacy messages for specific safety projects. Messages shared with Curbed show support for planned improvements to the city’s 17th Street corridor addressed to the city’s planning commission: “As a Bird rider, safer streets will make me feel more comfortable leaving my car at home.”

With Uber and Lyft managing options for more vulnerable street users, it’s overdue for these companies to jump into the safe streets conversation.

Scooter companies have drawn their share of ire, of course, which is why cities want to cap their numbers in an effort to control them. But there’s a better fix than limiting new options. If cities gave people more safe spaces to ride and park all modes of non-car transportation, both fans and critics would be happier. Imagine if, along with its scooter regulations, San Francisco announced a pilot program to expand Market Street’s 10-mph zone into a citywide, multimodal network, to be completed by the end of the summer?

That may sound impossible, but it could happen about this quickly. Seville, Spain—a city almost identical in size to San Francisco—built out a comprehensive “lightning” bike-lane network in just 18 months. The number of people commuting by bike daily increased tenfold in about four years. How did it work? The city carved out space from existing roadways—and eliminated 5,000 places to park cars.