Does owning a car hurt your health? To really answer that, you’d need a randomized trial:
But who’s going to assign long-term car ownership on the basis of a coin flip?
The city of Beijing, it turns out. Because of mounting congestion, Beijing has limited the number of new car permits it issues to 240,000 a year since 2011. Those permits are issued in a monthly lottery with more than 50 losers for every winner – and that, as researchers from the University of California Berkeley, Renmin University in China and the Beijing Transport Institute recently reported in the British Medical Journal, provides an elegant natural experiment on the health effects of car ownership.
Led by Berkeley economist Michael Anderson, the researchers followed 180 permit winners and 757 losers for roughly five years, and looked for differences caused by the acquisition of a car.
“The randomization of the lottery is what gives us confidence,” Anderson explained in a statement. “We know that the winners should be comparable to the losers on all attributes other than car ownership.”
Not surprisingly, the winners took 2.9 fewer rides a week on Beijing’s dense public-transit network, representing a 45-per-cent drop in usage. They also spent 24.2 fewer minutes each day day walking or biking than the non-winners, a 54-per-cent drop.
You’d expect these behaviour changes to have health impacts. Over all, the winners gained an average of just more than two kilograms, a difference that was not statistically significant. But the effects were more obvious when looking only at winners aged 50 or older: They gained an average of 10.3 kilograms, a statistically significant and worrisome increase.
In most Chinese cities, walking outside is a net harm to your health because of all the air pollution. Better to join a gym that has a good air filter.
You can suggest that being able to own a car even with risks to your health is preferable to not being able to own a car.
A lot of car ownership, in the west at least, is built around how much you value freedom of choice. Sometimes the availability of jobs depends on having a car: If you have a job not easily served by public transport, working at times when buses/trains don’t want to run (or in so doing charge a premium price), or a long way from home. A car make a lot of sense as it gives you the freedom to at least apply for the job.
A lot of factories many years ago had housing associated or close to them, so the workers could walk, but no one expects offices especially to build homes near them for the workers. In any event, businesses are more likely to move these days. Again, personal transport wins here. I have known people willing when a job base moves to drive up to sixty miles to work to keep the job.
The proponents of public transport don’t take that into account much, and often those proponents back a system of unions that frequently can and do go on strike for pay rises that the workers they transport cannot hope to get. They just get the inconvenience, or even lost wages.