Probably not the way it's done in the USA (from what I gather, drivers' licences are basically being handed out like candy), but the way it's handled in most European countries - requiring comprehensive education, practical exercise and independent examination on trafic laws, behaving in traffic and operating a car. The one thing we can learn from the US, though, is the absolute stigma against drunk driving, which is just not present to that extent. If cars were invented today, that's the one thing that'd probably change mechanically - a simple suite of sensors and a switch that shuts the engine down and engages the parking brake if the driver is drunk, fatigued or otherwise impaired.