How to Design Streets for People in the Era of Robocars

Autonomous vehicle technology could cut traffic and make city streets much safer. But it will require smart leadership. Graphic: NACTO
Autonomous vehicle technology could cut traffic and make city streets much safer. But it will require smart leadership. Graphic: NACTO

When automobiles came on the scene a century ago, motor vehicle interests reshaped cities dramatically, in many ways for the worse.

If you believe the hype about self-driving cars, another paradigm shift is coming, and the effect could be similarly transformative. But will it work for city residents or against them?

City officials are developing policy strategies to ensure that the advent of autonomous vehicles leads to less traffic, better transit, and safer streets for walking and biking. But those outcomes are far from guaranteed. To help cities advocate for their interests as autonomous vehicle policies take shape, the National Association of City Transportation Officials has released a “blueprint for autonomous urbanism.”

“This is the start of a critical conversation with AV companies about what cities need today and will need tomorrow,” said NACTO Executive Director Linda Bailey in a statement accompanying the report. 

Here’s a look at what NACTO thinks autonomous vehicles could mean for streets and transportation if we shape the technology to benefit cities.

More freedom to walk and bike

One non-negotiable rule is that car makers need to make autonomous vehicles safe without depending on people to wear sensors to be detected. If you’re walking or biking, you should absolutely not be required to carry special equipment, says NACTO.

In theory, companies should be able to engineer AVs to operate much more safely than human drivers. Negligent or reckless behavior like speeding and failure to yield should become a thing of the past. People who are intimidated at the thought of walking or biking on city streets with human drivers should feel reassured and liberated by the predictability of AVs.

The safety of AVs will depend in large part on limiting speeds in crowded areas. In dense neighborhoods where motor vehicles mix with pedestrians and cyclists, the maximum AV speed should be 20 mph, 25 at most. For the most crowded central city areas, vehicles should be programmed for even lower max speeds or to avoid the area altogether.

On residential streets, vehicles should also be programmed to travel at safe speeds with minimal stopping distances, so children can safely play and neighbors can congregate.

Faster buses

Savvy cities will want to do as much as possible to promote the use of space-efficient multi-passenger vehicles, instead of letting single-occupant robocars clog streets. For the same reason bus lanes make sense today, NACTO recommends cities carve out dedicated space for transit vehicles on major travel corridors once autonomous vehicles become ubiquitous.

Better accessibility

In a fully automated environment, NACTO recommends eliminating curbs in most places. This will eliminate the need for curbcuts for people using wheelchairs, who will have greater freedom to cross the street where they like.

Instead of curbs, cities can use bollards, different pavement textures, and other visual cues to differentiate space for vehicles from space for pedestrians.

Less space wasted on parking

Autonomous vehicles should greatly reduce the need for car ownership and parking. Cities should get ahead of that change by reducing or eliminating parking minimums, NACTO says, and insisting that new garages be easily convertible to other uses.

15 thoughts on How to Design Streets for People in the Era of Robocars

  1. On the parking, it’s worth noting that it doesn’t matter where AVs park, so long as they reach the end user when needed. Along those lines, AVs can park in one or more lanes of expressways at night. That space isn’t needed for capacity at that time of day. By avoiding the need for both overnight curbside parking and off-street parking, we can densify cities without necessarily changing zoning. Most cities have lots of parking craters which are amenable to development once they’re no longer needed for car storage.

  2. Good article!

    Regarding curbless streets… I’m not sure about that one, Roads need to be bowed for drainage, and without adding a crazy amount of new infrastructure, that could end up with water and debris pooling where people would like to walk most when it rains or snows..

  3. More Freedom to Walk and Bike should be expanded. I would include “no new pedestrian management devices to accommodate AV movement.” My fear, particularly in NYC, is that if, for instance mid-block foot traffic slows AVs to a crawl then DOT might see the need to erect physical barriers to prevent it. If there is enough foot traffic that AVs slow to that point then the solution should be to let them crawl or don’t let them in at all. Same with turning. If the AV can’t turn at an intersection without encroaching on pedestrians then it shouldn’t be allowed to turn. If city planners approach AVs with the same mindset they approached cars in the beginning of the 20th century — prioritizing vehicle speed over pedestrian freedom — then Manhattan could become a hellscape of sidewalk fences and pedestrian overpasses.

  4. I would love it if roads were inverted so that drainage collected in the middle. Not sure if that’s feasible though.

  5. There are places with both. The street slopes out, midblock, but the cement at the corner is level from the sidewalk to the crosswalk. This leaves a characteristic trap for any car wheel that tries to cut the corner. Alameda, CA has this, plus bollards.

  6. Build enough pedestrian overpasses and you’ve created a new elevated street level while the old street level has become non-tracked subways for bikes and other vehicles.

    But seriously, self-driving buses and vans are high occupancy vehicles that we should want to move us around quickly and efficiently. It doesn’t make sense for pedestrians to jaywalk at any time without considering how it slows buses to a crawl. That’s why traffic lights are either timed or intelligently linked to keep traffic flowing and enabling us to get places. A cost of living in a dense city instead of a mostly-trafficless town is everyone has to sometimes wait for traffic signals before moving. That means buses, cars, bikes, and pedestrians too. We all have to wait sometimes to give others a chance to pass.

  7. Happiness awaits. There are many reasons to believe the majority of future AV cars and buses will be single-width, leaving more room to walk and bike.

  8. Nobody wants to climb up overpasses, that’s separation of modes. The truth is that yes, the pedestrians are reckless, but, they should not be endangered by robots at turn points or slow streets where people cross mid block.

  9. “Autonomous vehicle technology could cut traffic.”

    So far the evidence is:
    – Autonomous vehicle technology is driving ride-hailing cost down.
    – Lower cost shifts people from mass transit to ride-hailing.
    – More ride-hailing is causing a surge in traffic and crashes.

  10. Very good point. The word is “crowned”. Drainage is also needed so water doesn’t’ pour into buildings. The sidewalk (or curbless area in front of buildings in NACTO’s vision) must slope toward the street and drains must be isntalled at the lowest point. Interesting that NACTO is describing a vision of safe shared space as opposed to separate spaces for motor vehicles, bicycles, pedestrians. Well, it’s a vision but it woudl require not only that autonomous vehicles be universal but also that existing streets be torn up and rebuilt. Not in my lifetime, I expect. Where do bicycles fit into this? With the confusion between sidewalk and street, I don’t think that works very well.

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