Unless we’re talking about hands-free voice commands, using your smartphone while driving is just an accident waiting to happen. We can tell people not to do it, and warn them of the risks, but in the end it’s up to drivers themselves to resist the temptation to check their Twitter feed while speeding down the highway. One company has devised a system that might be able to force even the most phone-crazy drivers to put their handsets down when behind the wheel, but ...