The collision left a visually impaired athlete, Japanese judo veteran Aramitsu Kitazono, with bruises, forcing him to miss competition over the weekend.

Kitazono was crossing in the crosswalk when the Toyota e-Palette, traveling at 1 to 2 km/h struck him. Toyota President Akio Toyoda apologized for the accident, while lamenting the limitations of today’s automated driving.

Under normal operations, Toyota said, the self-driving e-Palette—which has two human safety operators onboard—stops automatically when its sensors detect a pedestrian entering an intersection. The onboard operators then manually resume operations when they confirm safe passage. Human traffic directors in the intersections also help guard against accidents.

In last week’s case, however, the e-Palette and onboard operators activated the brakes too late.

Toyota will make several safety improvements in resuming service. First, the e-Palette’s warning sounds will be louder. Acceleration and stopping will be handled manually, not automatically. And e-Palette operators will get beefed-up training to account for a wider range of scenarios.

Meanwhile, the local infrastructure will be bolstered by increasing the number of human traffic directors at intersections from six to more than 20. At the same time, some traffic guides will be dedicated to directing vehicles; others will be responsible for handling pedestrians.

Toyota said it would work to refine and improve the technology over the course of the Games.

The accident cast a shadow on Toyota’s efforts to use the 2020 Olympics and Paralympics as a showcase for its automated driving prowess. As a top sponsor of the Games, it has marshalled a huge fleet of green cars and new mobility gadgets to shuttle people around the host city.

“It shows that autonomous vehicles are not yet realistic for normal roads,” Toyoda said during his apology.