BEIJING, Aug. 24 (Xinhuanet) -- Shanghai is considering introducing a congestion charge on motorists at peak times, in a bid to reduce traffic in downtown.

The proposal is included in a white paper issued yesterday, looking at ways to implement a vow by city traffic authorities to keep car volume within 2.5 million in central Shanghai.

With limited capacity to expand roads, city transport officials said they are researching congestion charges in specific regions or thoroughfares at certain times.

But officials gave no specific suggestions nor a timetable, and traffic experts believe that it would be difficult for the city to enforce the policy.

"Compared with Western countries, we have fewer cars but our drivers use them more than foreign counterparts," said Jiang Miankang, an official with Shanghai Construction and Communication Commission.

The city has about 1.77 million registered private cars, and the number is increasing by 200,000 annually.

"It's a tough question for all the city management," said Professor Yan Kefei of the transport school in Tongji University.

Yan said a congestion charge "is hard to implement," citing difficulties in managing such a scheme and driver resistance.

The professor said research into a congestion charge took place years ago, but that the idea was later dropped.

Officials said other traffic management measures are definitely on the way, following the city’s ban on vehicles with out-of-town plates on local elevated roads during rush hours.

Traffic authorities said they will "make adjustments on vehicle types, time spans and areas," with regard to freeway restrictions.

The city has about 500,000 vehicles with out-of-town plates.

As well as seeking to control car numbers downtown, transport officials are also trying to encourage motorists to use public transport instead.

The city's Metro system is set to reach 800 kilometers of track — up from the current 468 kilometers — while more bus-only lanes are being created.

"The guideline to develop public transport is correct," said Yan, who contributed to the city’s first traffic white paper in 2002.

"Ten years the focus was on construction, now we should look at management."

"Smart transport policy is to increase efficiency and handle demand and supply well."

Yan supports giving priority to pedestrians and cyclists.

Meanwhile, the paper also says that a fast Metro line is planned to provide a new link between Shanghai's two airports, Hongqiao and Pudong. It would link with neighboring cities in the Yangtze River Delta.

The white paper has been posted on the city government website and eastday.com.