Security video recordings on a double-decker bus that crashed in Shau Kei Wan on Monday showed the driver fainted and that the vehicle careened out of control for more than 10 seconds before it crashed into a taxi and another bus.
The footage showed the bus out of control as it ran down a slope on Chai Wan Road, New World First Bus operations head William Chung Chak-man said yesterday.
Chung promised to consider requiring company drivers to pass more stringent medical checks, including an electrocardiography (ECG), which measures hearts' electrical activity and detects irregular heartbeats.
The accident killed all three people in the taxi - cabbie Wong Kim-chung, 53; Swede Carl Lindgren, 30; and Briton Jorge Herrena, 34 - and left 56 injured. The two double-deckers buses sandwiched the taxi, crushing it at the junction of Chai Wan and A Kung Ngam roads.
The Mandarin Oriental Hong Kong confirmed that the two passengers who died were its guests, but did not name them.
"Both were uniquely talented, young chefs who were visiting the city on business and were senior members of [British chef] Heston Blumenthal's culinary team," the hotel's communications director Nina Colls said. "We are deeply saddened by this tragic event and our hearts and prayers are with their families and loved ones."
The pair, along with other staff from the Fat Duck, were on a promotional tour in Hong Kong.
A spokesperson for the Michelin-starred restaurant in Bray, Berkshire, said: "We can confirm two members of our team were tragically killed in a car accident. They were both senior members and great and dear friends.
"Two uniquely talented young chefs that were loved by everyone who worked with them. They will be sadly and deeply missed."
According to Chung, the video showed the instant when the driver, Lau Chit, 57, passed out and his head suddenly lolled back.
Chung said Lau took days off on Saturday and Sunday, and was also supposed to rest on Monday, but had volunteered to work.
Lau joined the company in 1998 and had a good driving record with only a few minor road accidents.
He passed his medical check in July.
"We are open to [including ECGs in the medical exams for those under 60]," said Chung. "We will discuss this issue with our medical advisers ."