BEIJING, January 1 -- A Chinese energy expert has suggested Beijing restricts the use of private cars and improves and expands public transport to achieve a sustainable development.

"The government should restrict private car use by economic means, but not by administrative or quantitative means," said Zha Daojiong, director of the Center for International Energy Security with the People's University of China.

He explained that the government should raise the cost of driving private cars, such as lifting oil prices and other charges, to restrict private cars, but not simply cut the number of private cars through imposing restrictions on car emissions.

"The capital city should also greatly boost public transport," he said.

Zha's views have been echoed by a local transport official.

"Beijing does not have policies to restrict the purchase or use of private cars for the time being, but that does not mean private cars can be used without restrictions," Liu Xiaoming, deputy director of the Beijing Municipal Transportation Commission, said.

However, Liu did not elaborate on any possible restrictions.

Liu said the city would greatly develop public transport and improve services in 2007 in a bid to make public transport more rapid, convenient and comfortable, and more appealing to the public.

By the end of November 2006, Beijing had 2.85 million vehicles, including two million private cars, and the number is increasing by 1,000 every day. The number is expected to reach 3.25 million in 2008 and 3.8 million in 2010, according to the Beijing Municipal Transportation Commission.

The proportion of private cars used for commuting increased from 23.2 percent in 2000 to 29.8 percent in 2005, while the percentage of commuters using public transport rose relatively slowly from 26.5 to 29.8 percent.

The city aimed to raise the proportion of citizens choosing public transport to more than 40 percent by 2010, Liu said.

It would raise the number of buses from 18,000 to 19,000 and 21,000 by 2010, and extend the metro from the present 114 km to at least 270 km, he said.