Shanghai car tags has jumped to a new high at this month's auction, and some auto buyers and industry experts are calling for changes to the way the city handles its growing load of motor vehicles.

The average winning bid price for a license tag was 47,711 yuan (US$6,278) at Saturday's monthly auction, the highest since the monthly auction began in 2000.

The price was 2,219 yuan higher than the previous record set in April 2004, and was up 2,858 yuan from May. The lowest winning bid jumped 2,700 yuan from the previous month to 47,200 yuan, also a record.

City government put 6,000 plates up for sale this month, about the same amount as in May. The number of bidders dropped 12 percent to 8,983, but competition was unusually fierce as bids have been rising monthly, said Yu Lili, a Chevrolet dealer.

"The price will probably top 50,000 yuan next month and could go further north and stabilize at 70,000 yuan to 80,000 yuan, equal to the price of a compact sedan," Yu said. "That would scare away some of the mid-class buyers."

China's passenger car sales have increased 20 percent this year, outpacing the 13 percent growth in the car plate quota.

Shanghai is now home to around one million vehicles. City government uses the tightly controlled monthly auctions to reduce roadway crowding and exhaust emissions. It is the only city in China to do so.

But many car owners have avoided the high cost by registering their vehicles in nearby cities, where the plate fees usually run from 4,000 yuan to 7,000 yuan. Drivers with out-of-town plates are not allowed to use Shanghai's elevated roads during rush hours, however.

"The plate auction system is helping Shanghai balance building an adequate road network and a rapidly expanding vehicle population," said Sean Zhou, a traffic engineer at MVA Transport Consultants Co Ltd, a transport planning firms.

"In addition to quickening its pace in developing public transportation, Shanghai could also learn from other metropolitan areas to handle the conflicts between people's eagerness to own cars and city planning."

In big cities such as London and Stockholm, private car owners pay congestion charges when they drive into downtown areas or commercial centers in rush hours, which limit people's use of private cars without discouraging vehicle purchases.

Despite growing complaints from car buyers, city government says it has no present plans to increase auto licensing.

Wu Zhenguo, deputy director of the Shanghai Development and Reform Commission, said during a government news conference in May that "the auction is in line with the city's overall urban development blueprint and its long-term policy that encourages people to take public transport."

"Relaxing controls (on tags) could damage the city's environment, lead to mounting pressure on the city's roads and undermine the city's previous efforts," Wu said.