Beijing enjoyed its best air quality in a decade during the Olympic Games, thanks in part to strict traffic-control measures. Pleased by their success, city officials have unveiled ongoing modified measures in hopes of continuing to ward off the smog. Under rules that go into effect Oct. 11, privately owned vehicles will be banned from driving on one weekday, with the particular day determined by license plate number. A third of government vehicles must stay off the roads each day as well. City authorities are encouraging employers to adopt more flexible working hours or allow telecommuting, and the program will be reassessed after six months. Beijing residents currently buy some 1,000 new cars each day. If one resident’s response to the new plan is any indication, the new measures could have unintended consequences. “I need to take my daughter home from boarding school on Friday night,” says Zhang Min, whose license plate number disallows him from driving that day. “Probably we need to buy another car.”