New rules forbid drivers from drinking alcohol within eight hours of starting work and ban them from "excessive" drinking at any time, the Xinhua News Agency said.
The rules are the latest in a long list given to Beijing residents, police and almost anyone involved in the Olympics warning them to stop spitting, be polite, learn English, wait in lines patiently, and be nice to the hundreds of thousands of visitors expected for the Summer Olympics.
The Games start in just under one year.
Xinhua said the Municipal Bureau of Quality and Technical Supervision issued the rules "to ensure an orderly public transport system."
Conductors were also warned that they were "forbidden to chat with the driver on the job."
Road accidents are common in China because of overloaded and unsafe vehicles, poor road conditions and bad driving. Last year, about 90,000 people were killed on China's roads, according to the Ministry of Public Security.
While drunk driving is not considered a problem relative to other countries, police in the capital Beijing and other cities have begun cracking down on the practice.