The surveys showed that about half of urban private car owners thought the fees for car maintenance and oil consumption were "affordable" in 2005, but only one out of five in the 2007 index thought so.

"Driving is a kind of burden to me. Last Friday, fuel prices started to rise again, which means every month I have to pay an additional 300 yuan ($44). I believe more than 20 percent of car owners will use public transport by next week," said Chen Daping, a 30-year-old worker in Beijing.

"It costs me only 1.8 yuan to take the bus from Tian Tongyuan in Changping district to Anzhenli in Chaoyang district, but more than 20 yuan for gasoline to drive a car. What a deal!" wrote an Internet user under the name of "tyy Ma" on news portal Sina.com.

The high costs were not the only reason for the increasing number of owners of idle cars. Traffic jams also played a role, researchers found.

The economic loss caused by traffic jams in Beijing was the highest among the cities in the country, about 375 yuan per person per month, followed by Guangzhou at 273.8 yuan and Shanghai at 228.2 yuan.

The researchers said convenient public transport networks should be developed to help solve the problem effectively.

Beijing has reportedly done a good job in developing a convenient and affordable public transport system, which was ranked first in the survey.

The survey showed that about 21.3 percent of respondents suggested improving public transport routes to help alleviate traffic congestion, while 14.3 percent said special lanes should be arranged for buses. The rest suggested improving road conditions and limiting private car usage.