The drivers are from 476 organizations, including 380 drivers' clubs and 28 private and overseas-funded businesses, said Wang Xiaoming, of the Beijing Municipal Environmental Protection Bureau, citing statistics from a local drivers club.

A random sample survey released by the Beijing Social Psychology Institute on Tuesday shows that more than 80 percent of drivers in the city's eight urban districts have heard of the "no car day" operation, and 42.3 percent voiced "strong support" for it, hoping it would improve traffic and air conditions.

The survey also shows that half of the drivers who promised to leave their cars at home will choose buses or subways as their means of transportation during the Forum on China-Africa Cooperation scheduled from Nov. 1 to 5, which will attract about 40 African state leaders.

To ensure smooth traffic for the forum, Beijing will restrict the use of vehicles belonging to government departments and state-owned enterprises, and shorten school hours to ease traffic congestion, the Beijing Transportation Committee has said.

Half Beijing's army and central government vehicles and 80 percent of Beijing municipal government department cars will be banned from city roads during the forum, according to the committee.

The plan is understood to be a practical rehearsal for traffic arrangements during the 2008 Olympics.

Meanwhile, Beijing will increase bus and subway train services to ease traffic congestion in the period, the committee said.

A city with a population of about 16 million, Beijing now has 500,000 company cars and 2 million private vehicles.

The Beijing "no car day" operation, launched in May this year by more than 100 drivers' clubs, encourages drivers in the city to leave their cars at home at least one day a month in order to ease traffic jams, reduce noise and improve air quality in the Chinese capital.

The campaign comes as Beijing endeavors to hit its target of 238 "blue sky days", or days with fairly good air quality this year.

For the first ten months, the capital has reported 203 "blue sky days", one day more than the same period last year, the local environmental protection bureau said on Wednesday.

In 1998, when it only had 100 days of "blue sky", Beijing launched a project called "Defending the Blue Sky".