Teens whose parents set rules of the road and enforce them are more likely to be safer while behind the wheel than their peers without that parental support and communication. In fact, having family driving rules has been shown to reduce teen crashes by as much as 50 percent (and to reduce the odds your teen will drink and drive by as much as 71 percent) [source: GHSA]. Be clear about what your rules and expectations are, such as curfew and number of passengers allowed (if any).
Also understand and follow your state's licensing requirements; for instance, all 50 states have some type of graduated driver licensing (GDL) program, which slowly introduces risky on-the-road situations such as nighttime driving to novice drivers over a set period of time. It's a program that works (it's reduced the number of crashes at the hands of young drivers by as much as 20 to 40 percent), but only when parents stay involved [source: GHSA].