Transport service companies will be required starting in fiscal 2010 to conduct sobriety tests on their drivers before they start work for the day, government sources said Monday.

The move to eradicate accidents caused by drunken drivers comes as the transport ministry found that tests by truck, bus and taxi service operators are insufficient, as they do not require a Breathalyzer.

The Land, Infrastructure, Transport and Tourism Ministry is also planning to toughen penalties for operators this fiscal year. The number of professional drivers caught drunk behind the wheel was 463 in 2005 and 477 in 2006, but then declined to 352 in 2007 and 287 in 2008, according to the ministry.

Numerous employers have already introduced breath tests independently, following the enactment of the amended traffic law that imposes harsher punishments on drunken driving.