BEIJING, April 27 (Xinhua) -- With the approach of the May Day holiday, traffic control authorities are warning drivers against dangerous activities like drunk driving, overloading their vehicles, speeding and driving while tired.

The holiday, which will last from April 29 to May 1 this year, will see millions of Chinese traveling across the country by automobile.

Traffic during the holiday is expected to increase by 15 to 20 percent compared to last year's holiday, according to the traffic administration under the Ministry of Public Security.

Heavy rain will make driving difficult in some parts of the country, particularly south China, the administration said, adding that drivers should plan their routes carefully and learn as much as they can about current traffic conditions before traveling.