(BEIJING, August 10) -- Beijing plans to cut the number of vehicles on the roads by 1.3 million in a four-day test to ease traffic congestion and see how much the air quality changes, officials announced on Friday.

From 17-20 August, in the midst of the Good Luck Beijing sports events, the municipal government will take restrictive measures and collect data on the interrelation between the emission cut and air quality improvement, thus accumulating experience to ensure a favorable environment for next summer's Olympic Games, Du Shaozhong, spokesman for the Municipal Environmental Protection Bureasu told a press conference at Beijing Olympic Media Center.

During the period, 70 percent of government and enterprise-owned vehicles will be ordered off the roads, and personal vehicles must follow the license plate system: on August 17 and 19 (Friday and Sunday) only vehicles with a licensed plate number ending with an odd numeral will be allowed on the roads, and on August 18 and 20 (Saturday and Monday) they will be replaced by those with plates ending with an even number, said Liu Xiaoming, vice-director of the Municipal Communications Commission.

In view of Beijing's total vehicle volume of 3.05 million, of which 2.46 million are privately-owned, the number of the vehicles off the roads is expected to reach 1.3 million, he said.

The new measure is expected to bring a reduction of emissions by 40 percent and an increase of traffic speed to an average of 33 kilometers or even 55 kilometers on the expressways from an average of 19.25 kilometers now, Liu added.

To take on an additional two million passengers that usually use cars as their transport means, the city's public transit system will add a capacity of 700 to 800 buses, and rush hour services of Beijing's 144-kilometer subway system will be extended by one hour in the morning and three hours in the evening.

Du said similar measures were taken in Atlanta and during the Athens Olympic Games, which had a positive impact on air pollution. During the Sino-African Summit in Beijing last year, traffic restrictions also yielded good environmental results.

Although Beijing has done a lot to cut emissions and improve air quality, air pollution remains a problem because of the booming number of vehicles from 1.3 million in 1998 to more than 3 million today.