Inside the self-driving bus Zuyaro, a screen displays the vehicle's current performance./Sung Yu-jin

On the morning of May 27, a bus traveling on a four-lane road in Dongan District, Anyang, Gyeonggi Province, in South Korea, stopped when it encountered an illegally parked car next to the sidewalk. The bus waited until the neighboring three lanes were clear of passing cars, then switched lanes and resumed driving.

This decision was made by the bus’ autonomous driving system, not a human driver. The autonomous bus, named “Zuyaro,” is a Level 3 autonomous vehicle (requiring driver intervention only in certain situations, such as emergencies) that has been operating on the roads of Anyang since April. Although a human driver was present, the bus operated autonomously for most of the journey, except when leaving the depot and turning around at the end. During a 15-minute ride, the experience was similar to that of a regular bus.

Safety was a noticeable priority in its design as a public transportation system. The buses traveled 40 kilometers per hour or less, which is slower than the speed limit of 50 kilometers per hour. There was no dangerous weaving in and out of traffic or rushing through traffic signals. Standing is prohibited, and the gates were manually opened and closed to prevent accidents.

A driver takes his hands off the wheel of Zuyaro, a self-driving bus in Anyang./KT

KT Consortium, responsible for Zuyaro’s operations, applied various technologies to enable autonomous driving. An existing 25-seat electric bus was converted into an 18-seat vehicle equipped with four lidar, five cameras, and one radar. These devices recognize nearby vehicles, obstacles, terrain, pedestrians, traffic lights, and other situations to help the autonomous driving system function properly.

KT also utilized its ultra-precise positioning technology, RTK-GPS (Real Time Kinematic Positioning), which corrects GPS errors and enables real-time location information to be accurate to the centimeter. “The more accurate the location information is, the more it can prevent the autonomous vehicle from driving in the wrong lane or missing the right or left turn entry point,” KT explained.

The Intelligent Transportation System (ITS) data that KT and Anyang City have been building since April last year will also be utilized. The ITS can identify road conditions through road surveillance cameras (CCTV) and detect unexpected situations such as pedestrian jaywalking, illegal turns and reversing, and falling objects. This information is then transmitted in real time to the safety manager on board the Zuyaro.

KT stated, “In addition to the sensors on the vehicle itself, the ITS data is also utilized to increase driving safety.” During Zuyaro’s testing phase, there was a collision, but the insurance company determined that Zuyaro’s negligence was 0% (the other vehicle was 100% at fault).

AI technology was also applied. “There are quite a few illegally parked vehicles around the bus stop in Anyang City, so the autonomous vehicle has to change lanes to avoid them and find the best place to stop,” said Choi Kang-rim, head of KT Mobility business division. “We use AI to learn this process and continuously improve the route.”

Zuyaro, a self-driving bus in Anyang, South Korea, on the road./KT

Zuyaro will operate on two new routes: a day route (10 a.m. to 5 p.m.) and a night route (midnight to 2 a.m.). “We prioritized public transportation underserved areas and vulnerable hours in the route and time zone design,” said an official from Anyang City. Bus operators struggling to monetize their routes have been receptive to building an autonomous bus system.

The industry sees autonomous buses as a key solution to reducing areas with poor transit coverage. By operating autonomously during nighttime hours, they can help alleviate labor shortages. In rural areas, they can serve as demand-responsive public transportation, adjusting routes and operating hours according to passenger demand. Seoul Metropolitan Government has been operating autonomous buses during late-night hours, from 11:30 p.m. to 5:10 a.m., between Hapjeong Station and Dongdaemun Station since late last year.