A total of 110 people were injured yesterday when four coaches crashed into each other in the rush hour in Kwai Chung - believed to be Hong Kong's biggest single accident toll in 20 years. Police were last night searching for the driver of a Mercedes-Benz who allegedly sped off after his vehicle and one of the coaches collided at about 8.15am outside Princess Margaret Hospital. The collision caused the coach to swerve, leading the three other coaches to crash. The car sped off, said Superintendent Li Chiu-keung, of the New Territories South traffic unit. He said passengers on one of the four coaches escaped through the emergency exit as the main door had been badly damaged. One of the coach drivers was trapped and had to be freed by firemen. Traffic was badly disrupted for almost three hours after the crash as police closed the four Kowloon-bound lanes of Route 3 in Kwai Chung. Police said traffic was backed up to Tuen Mun Road near Tsing Lung Tau and to the Tsing Kwai Highway on Tsing Yi. The 110 victims, including three drivers, were taken to five hospitals by 14 ambulances. Last night, three of them were in serious condition in Princess Margaret Hospital. Two others were in stable condition in Yan Chai Hospital. The other 105 victims were discharged after treatment. New Territories South divisional officer Lau Chi-ho, of the Fire Services Department, said only the trapped driver and two passengers needed to be removed from the scene on stretchers. He said about 200 people were travelling on the four coaches and most of those hurt suffered minor injuries to their heads, hands and legs. Police said the coaches had been ferrying passengers to work from Tuen Mun, Yuen Long and Tsing Yi when the accident happened. Yesterday's incident is believed to have involved the largest number of casualties in two decades. In 1982, a man was killed and 109 people were injured when a Kowloon Motor Bus double-decker crashed into a hillside. An oil tanker flipped over on to its side while travelling in a Kowloon-bound lane of the Tuen Mun Highway last night. Police closed a section of the road for four hours while the spill was cleaned up. Twenty-four bus routes were diverted into Castle Peak Road.