Much has been made of Beijing's decision to keep a lighter version of its Olympics traffic restrictions, not least because whatever the city did to clean the air seemed to have worked in August. But the renewed measures are weaker and the probable effect is unclear.
Alex Pasternack at Treehugger points out that the sustained restrictions, which took effect October 1, will be weaker than during the Games. Only one fifth of cars will be pulled from the road on weekdays, versus half under the Olympics rules.
According to The Beijinger (also via Alex), the city's other restrictions include:
- Restricting the number of car license plates issued for the city every year to 100,000--one fourth of the current rate of new car registration. This may in the long run be the most powerful measure, because it will reduce the extent to which increased wealth leads many people to obtain cars.
- Raising parking prices. If it costs more to park, maybe people will take the...
- Growing public transportation network. Lines five, ten, eight, and the airport express opened in the year leading up to the Olympics. Expansions of existing lines and other new lines are planned in the next two to three years.
But it's hard to tell whether the automobile and transportation efforts were really the core of Beijing's cleaner skies during the Olympics. For one thing, it's useful to remember that before a series of rainstorms, many people didn't feel the skies were particularly clear. Afterward, opinion among those used to standard Beijing air was uniformly laudatory. The rain may have helped clean things up.
It is difficult to assess, too, how important the other measures taken around the Olympics were. Manufacturing was slowed or stopped all over the region. Some of the dirtier power plants were shut. (Some may still be shut, but reports indicate that much of the industry has reopened.)
And significantly, dust from construction, a major fact of life in contemporary Beijing, was halted, because construction was halted. Though the surge of building that led up to the Olympics will probably not be matched in the near future in that city, some construction will restart.
So, to the extent that the sustained restrictions on driving decrease people's emitting behavior, that's great, but only time (and reliable measurements of air quality over time) will give a fair estimate of the effect.