Could Self-Driving Buses Bring Vehicle Autonomy Home?

In the race to develop autonomous vehicle technology, some companies are steering away from robotaxis to explore a different avenue: driverless buses. With an anticipated shortage of qualified bus drivers looming and concerns growing about the relative inefficiency of robotaxis, companies are opting to equip city buses with advanced levels of autonomy.

This a far better application for autonomous vehicle tech than robotaxis, says Kevin DeGood, the director of infrastructure policy at the Center for American Progress in Washington, D.C. “The two modes are totally different in how they affect congestion. Buses and rail reduce congestion, while robotaxis increase it. The congestion comes from increased deadheading by ride hailing vehicles.” Deadheading, DeGood explains, is when a vehicle is operating without any passengers.

“Buses don’t deadhead, except sometimes when out of service,” DeGood says. “During peak periods, a city bus often carries several dozen people. The average robotaxi carries one.”

Who’s in the Lead?

Current self-driving bus trials involve buses operating at Level 3 autonomy, where human input is required occasionally. These trials are taking place on private campuses such as universities and medical centers, where traffic is light and speeds are low. The next goal involves rolling out Level 4 autonomous buses capable of navigating public roads without human intervention.

The San Jose-based Imagry is leading this charge. It makes an autonomous driving software stack that it sells to automakers. It also retrofits standard electric buses with its self-driving tech and sells the finished buses to municipal mass transit agencies. The company, founded in 2015, was initially focused on computer vision for various applications.

In 2018, Imagry pivoted to ride the wave of enthusiasm about autonomous driving. In 2023, the company launched an autonomous bus project at Sheba Medical Center in Ramat Gan, Israel—the largest hospital in the Middle East. Not long after that, Imagry received approval from the Israel Innovation Authority to operate autonomous electric buses in the city of Nahariya. Those successes spurred the company’s leadership to scale up production and go global. Imagry has since submitted bids to operate autonomous buses in Austria, Germany, Japan, Portugal, and Sweden.

“During peak periods, a city bus often carries several dozen people. The average robotaxi carries one.” —Kevin DeGood, the Center for American Progress

For now, the company’s buses rely on Level 3 technology, operating routes with a human driver behind the wheel as a precaution. But the company’s CEO, Eran Ofir, told IEEE Spectrum that Imagry is working to secure the first-ever Level 4 certification for a standard city bus by the third quarter of 2025.

“Based on our track record, we’re confident that our buses will meet the standards set by the respective rule-making authorities,” Ofir says. Ofir added that there has been no movement in this direction in the United States, because although Imagry has operated autonomous vehicles on public roads in Arizona, California, and Nevada, the regulatory environment there does not yet support self-driving buses.

Asked about the benefits of fielding an autonomous city bus over a fleet of private cars, Ofir agreed with DeGood’s assessment. He notes that not only do robotaxis exacerbate roadway congestion because they greatly increase the number of miles driven in a given 24-hour period, they’re also less attractive as a business proposition.

“Imagry is not doing robotaxis because we believe it’s a domain with a problematic business model,” Ofir says. “The hardware that is installed on those vehicles costs between US $70,000 and $100,000. You cannot take that solution into the average passenger vehicle that costs $30,000 or $40,000. It will take two or three years to see any return on that investment.” That concern about cost, he says, is why Imagry does not use lidar or radar systems. Instead, its system relies on cameras, which are much cheaper.

Imagry’s buses are equipped with eight specialized cameras, each monitoring a unique aspect of the environment. One tracks traffic lights, another monitors pavement markings like crosswalks and lane dividers, and yet another keeps an eye out for pedestrians. A machine learning algorithm merges the data from these cameras into a high-definition map. This map provides the bus with a comprehensive view of a bus’s surroundings, accounting for everything within a 300-meter radius. This allows an onboard deep neural network in charge of movement planning to reliably make decisions about accelerating, braking, switching lanes, or turning.

The self-generated map approach offers some advantages, according to Imagry’s CTO Ilan Shaviv. Compared with centralized mapping systems, he says, maps on the fly require less computing power and eliminate the need for a communication link to an external map—an entry point that could be exploited by cyber attacks.

Self-driving Bus Competitors

Imagry is by no means alone in the self-driving bus field. MAN Truck and Bus Company has a partnership with Mobileye in which the two companies are pairing Mobileye’s EyeQ systems-on-chip for sensing, mapping, and driving policy with MAN’s commercial vehicles.

Bus manufacturer Karsan has developed e-ATAK electric buses that use lidar, radar, visual light cameras, and thermal cameras to sense and keep their distance from living or non-living objects and keep track of its position with respect to its environment. Iveco and EasyMile have jointly developed a Level 4 autonomous bus that they hope to get certified, pending Level 3 tests. Their bus also features vehicle-to-infrastructure capabilities that allow the bus to anticipate the phases of traffic lights. Previous research has shown that this ability means smoother stops and restarts with less energy. And when the bus is done making its appointed rounds, the onboard tech lets the bus maneuver itself into a parking space in the depot.

Governments across Europe and Asia are embracing this shift. And if the Level 3 trials open the door for Level 4 autonomy on city buses, the days of chatting with a bus driver and asking for suggestions about places to eat, shop, or sightsee—or what parts of town to avoid—may be increasingly in the rearview mirror.