Cities Face a New Traffic Threat as Self-Driving Fleets Expand

A rapid expansion of self-driving vehicle services risks producing the kind of congestion and street redesign that accompanied the original rise of the automobile, transportation experts and urban planners warn. With companies including Waymo, Tesla and Zoox already carrying hundreds of thousands of weekly autonomous trips in parts of the United States, and ride-hail operators signing large robotaxi deals, cities face a choice: update rules now or contend with a potentially chaotic transformation of street life.

Autonomous vehicle (AV) deployments that were once experimental and localized have begun to scale. Waymo, which operates in several markets, runs about 300 vehicles across Los Angeles County, and companies have announced service expansions in Austin, Los Angeles and Las Vegas with plans for future rollouts in Dallas, New York City, Philadelphia and Miami. Uber has also agreed to deploy tens of thousands of robotaxis powered by another AV company, reflecting growing private-sector momentum in the market. Proponents point to safety and convenience gains — AVs cannot drive drunk, distracted or tired and can make trips less stressful — but planners say those benefits could increase total vehicle miles traveled and throttle city streets.

City officials and researchers cite several mechanisms by which AVs could worsen congestion. Freed from the burdens of human driving, people may take more and longer trips. Deliveries may proliferate as labor costs fall. A persistent problem known as “deadheading”—vehicles circulating empty while en route to a pickup or waiting to be summoned—already affects ride-hail services; researchers have found that Uber and Lyft vehicles are passengerless roughly 40 percent of the time. If AV fleets scale up by orders of magnitude, those empty miles could multiply.

Even an electrified AV fleet would not eliminate all public-health concerns, planners say, because electric cars still generate particulate pollution from tire and brake wear. Increased car volumes could also slow buses and other shared modes, further undermining public transit and widening the gap between riders inside private AVs and those on foot or on buses stuck in gridlock.

Analysts emphasize that the arrival of AVs does not have to repeat the negative pattern of the early auto era, when cities reconfigured streets to prioritize cars, eroding pedestrian space and public life. Municipal leaders can use existing policy tools and new ones adapted to AV behavior to shape outcomes.

One widely cited measure is congestion pricing. New York City instituted a weekday fee for vehicles entering Manhattan below 60th Street earlier this year, and officials reported sharper traffic flow and reduced noise within months. Cities could adopt similar charges for AVs and other vehicles to discourage unnecessary trips. Planners also propose mileage-based fees that penalize empty miles and dynamic pricing that scales fees inversely with vehicle occupancy to encourage pooled trips.

Managing curb space will be another immediate and practical challenge. Unlike private cars that park at a destination, robotaxis will circulate or seek short-term stopping areas for pickups and dropoffs. Many municipal inventories of curb rules and loading zones are outdated or incomplete, making it difficult to assign pickups to places that minimize disruption. Alex Roy, an autonomous vehicle consultant, said AVs may stop in traffic lanes if suitable curb spaces are unavailable, creating safety risks for pedestrians and bikes. Robert Hampshire, who helped oversee federal curb-management grants at the Department of Transportation, said creating a current, digital map of curb space should be a priority so cities can coordinate pickup/dropoff zones and reduce double-parking.

Some cities are testing solutions. Philadelphia piloted “smart loading zones” that drivers and delivery services can reserve via a smartphone app. San Francisco has experimented with dynamic parking pricing that adjusts to real-time demand to maintain availability. Planners suggest converting underused parking areas into housing, parks or wider sidewalks as demand for long-term vehicle storage falls. Dozens of cities, including Austin, Raleigh and San Jose, have already removed zoning-mandated parking minimums to reduce development costs and promote more space-efficient travel modes.

Enforcement is another point of leverage. In several Bay Area deployments, AVs have impeded emergency vehicles, stopped in bike lanes and paused in intersections. Because violations are often brief and police resources limited, companies face weak immediate penalties; that, officials say, incentivizes AVs to prioritize passenger convenience over compliance. Municipal leaders are pushing for automated enforcement systems that can reliably fine illegal maneuvers by humans or algorithms. Studies of automated red-light and speed-camera enforcement indicate such systems can deter violations and win public support where they are permitted. However, many U.S. states restrict the use of camera-based citations, and city officials say loosening those limitations is necessary to ensure consistent enforcement of curb and lane rules.

Industry players have not offered on-the-record rebuttals to every policy concern. Waymo did not comment for this story, and Zoox and Tesla did not respond to requests for comment. AV operations have proved costly: Waymo reported an operating loss of more than $1 billion in the first quarter of this year, underscoring that a fully commercialized robotaxi market would likely require substantial scale or lower technology costs before fleets expand dramatically.

Experts stress that the timeline for mass AV adoption remains uncertain, but that uncertainty is not a reason for inaction. Jinhua Zhao, a professor of cities and transportation at MIT, argued that many policy responses would improve current urban life even if autonomous fleets take much longer to scale. Jeffrey Tumlin, formerly San Francisco’s director of transportation, said the right pricing and curb management would preserve access and circulation while creating revenue that cities can reinvest in public transit and safer streets.

Municipal leaders will have to coordinate with state and federal authorities on some rules, but many steps are available now: adopt congestion or mileage charges, inventory and digitally map curb assets, eliminate parking minimums, price on-street parking dynamically and expand legal authority for automated enforcement. Planners say those moves can reduce the chance that autonomous vehicles remake cities in the image of a 20th-century car-dominated landscape and can protect transit riders and pedestrians as AV technology matures.

The experience of the last century shows how quickly urban life can change when new vehicle technology scales. City officials and advocates say deliberate policy choices made now can steer this transition to support livable streets and reliable transit rather than replay past mistakes.