City: Beijing

Starting: 2011

Measures taken: The city allowed 240,000 vehicles to be registered in 2011, 70 percent fewer than in 2010. The quota is the same this year. Applicants can take part in a monthly lottery to win the right to have a car registered.

Reasons for the policy: The number of vehicles in the capital has increased quickly in the past several years. It stood at 4.81 million at the end of 2010, up from 2.6 million in 2005. IBM, the technology and consulting company, conducted a global survey in 2010 and found that Beijing shared with Mexico City the distinction of having the world's worst commute.

Results: Only 174,000 new cars were registered in 2011, the smallest number seen since 2000, according to traffic officials. And Beijing's new car sales plummeted to 403,500 units in 2011, a year-on-year decrease of 56 percent.

The average Traffic Performance Index in downtown Beijing, which gauges traffic congestion, dropped from 2010's 6.1 to 4.8 last year. A ranking of between 4 and 6 indicates light congestion and one between 6 and 8 indicates moderate congestion. At the end of May, there were 5.08 million vehicles in the city.

City: Shanghai

Starting: 1994

Measures taken: Shanghai is the only city in China that uses an auction to control the supply of license plates. The system allows bidders to offer a price for a license using their phones or the Internet. Whoever bids first and offers a price above the threshold price, which fluctuates every auction in accordance with the current demand for licenses, will receive a plate.

Reasons for the policy: The Shanghai government regards it as a way to alleviate traffic congestion in the city, although the local media report almost every year that the bidding system will be replaced with more effective measures.

Results: Shanghai license plates, called the single most expensive pieces of iron in China, started going for the record high price of 64,367 yuan ($10,100) in May. Since the beginning of 2011, the record price at auction has been broken more than 10 times, and the average price of plates has increased by more than 2,000 yuan every month since the beginning of this year.

Even so, the number of private cars on Shanghai's roads is still increasing by 8,000 a month despite the higher prices. Aspiring drivers have taken to buying license plates from nearby cities and provinces.

(China Daily 07/02/2012 page5)