The website conducted another survey, in which nearly 400,000 Internet users participated; 67 percent agreed that "banning private cars from the road is unreasonable" and supported the ban on government cars; 28 percent said it would contribute to cleaner air and better traffic flows.

Early in the new traffic ban, public debate continues and some Internet users are even questioning the legitimacy of such a policy.

The government maintains the Law on Road Traffic Safety and the Beijing municipal government's Regulations to Implement Law on Prevention of Air Pollution give it the right to limit motor vehicles on the road to optimize traffic and air quality conditions.

Gan Peizhong, a law professor at Peking University, supports vehicle restrictions but thinks local government has sidestepped the legislative process with the new ban.

"There are serious flaws in the procedure," he says, claiming the public should have had the chance to express their concerns before it was implemented. Nor is he convinced this is the end of it. "We cannot predict what the government is going to do after the trial," he says.

There is also a belief that private cars are personal assets under the Property Law, in which case owners have rights pertaining to their ownership, use and disposal.

Beijing lawyer Li Dejia says the government's good intentions should not be at the expense of citizens giving up their rights to private property.

"But I can still understand that the government is trying to balance the long-term public interest and a short-term conflict," he says.

Prof Zhang Ming, of Renmin University, is less understanding and strongly opposes the ban on private cars. "Some small business people depend on their cars to make a living and a day without their car will cause a loss of income," he says.

Zhang suggests that more government-owned cars be banned. "The government has a lot to do to improve Beijing's air and traffic," he says, "but one thing it shouldn't do is ban private cars from the road."

He also fears the government might in future apply the same logic - personal sacrifice for the good of the majority - in other areas of life.

As for distressed mother Zhang Ximan, she says: "I don't know how long I can put up with all this inconvenience. Isn't there anything else the government can do to improve the air and traffic?"

She is now considering circumventing the ban by doing something available to very few Beijingers. Having made a fortune as a developer in the real estate industry during the boom, she is now thinking of ... buying a third car.