A 64-year-old bus driver had a stroke and partially fell unconscious while driving on the Tokyo Bay Aqua-Line Highway in Chiba Prefecture on Tuesday, hitting a car ahead of him and straying onto the median strip, police and bus operators said Thursday.

The bus averted a major accident when a passenger noticed the driver's ill health and stepped on the brakes for him. Nobody, including the roughly 30 passengers on the bus, was injured.

According to the Chiba Prefectural Police and Kominato Tetsudo, the operator of the express bus services, the bus, which left Haneda airport and was bound for Kisarazu Station in Chiba Prefecture, bumped onto the median strip just 800 meters before the Kisarazu Kaneda tollgate at around 6:20 p.m. Tuesday. It also rear-ended the car.

After the bus was stopped, the driver was taken to a hospital and regained consciousness. He had no history of major illnesses and was in good health at the start of his shift, the bus company said.

"We will make sure the health of our staff is rigorously checked, and will ensure safety by introducing automatic brakes," a representative of the bus company said. "We are also grateful for the passenger who engaged the brakes."