When your kid graduates to driving on an actual street, pay attention to what he's paying attention to. Is he taking little glances at the curbs where there might be important signage or kids chasing errant kickballs? Is he checking the rearview mirror every once in a while? You're most likely to drive where you're looking, so make sure his attention is on the street ahead, not at his friend standing on the sidewalk -- unless you want to end up on that sidewalk yourselves.
Also make sure your kid hasn't, as it's called in the novel "Watership Down," gone tharn. That's when the rabbits end up in the middle of the road staring into the approaching headlights as they bear down on those fuzzy little bunny bodies. Your kid's face should not look like that. He should be watching and registering what's happening, not freaking out in wide-eyed panic.