Driving on camera

THE idea of fitting a car with a video camera only struck many motorists as a good idea in February 2013. That was when a meteor streaked over Chelyabinsk in Russia before exploding, injuring more than 1,000 people and damaging thousands of buildings. Soon after, videos of the giant fire ball began to appear online—which in an age of ubiquitous smartphones is, perhaps, not surprising. But what was rather unusual is that a dozen or so were filmed by small cameras mounted on the dashboards of cars—dash cams, as they are called. Such devices are growing in popularity as increasingly sophisticated cameras come to market. But why would motorists want them and what do they do?