The city of Beijing continues to grow rapidly, not only in population, but also in the number of vehicles on its roads. Although this increased mobility has benefits, the city has become one of the most polluted and gridlocked in the world. Driving restrictions have often been regarded as a silver bullet by various countries and regions seeking to mitigate congestion and pollution problems—including Beijing. However, as has been observed in areas that introduced similar programs, this type of command-and-control policy produces unintended consequences, and Beijing is no exception.
During July 17 to 20, 2007, Beijing became the first city in China to implement a driving restriction policy. It was estimated that this four-day experimental restriction—a trial run for the 2008 Olympic Games—took about 1.3 million automobiles off the roads. After the Olympics, evidence of reductions in traffic congestion and pollution encouraged the government to continue with a similar but less restrictive program. The congestion index—which measures congestion on a scale from 0 to 10—was reduced substantially, shrinking from 7.95 in 2007 to 5.93 in 2009, even though the vehicle population increased by 26 percent in 2007.