It’s one of the most nerve-wracking moments in parenthood: handing your teen the car keys and watching her drive off … for the first time, alone.

You try to ignore the “What-ifs?” and remember that this is part of life. You hope your budding driver will use the blinkers, obey speed limits … and never drink and drive. The national Centers for Disease Control and Prevention has good news on that last one: Survey data shows drinking and driving among high-schoolers age 16 or older has dropped by more than half since 1991.

That’s a big improvement. Today it’s estimated that nationally, only 10 percent of teens drink and drive. Boys age 18 and older are most likely to do so.

But some grim realities remain: high schoolers drink and drive about 2.4 million times per month. Those who do are very likely to binge drink, meaning they’ll consume five or more alcoholic beverages in a few hours. And alcohol is involved in 20 percent of fatal accidents that include teen drivers. Scary stuff.

The C-D-C emphasizes that communities and families must cooperate to curb teen drinking. Parents, practice what you preach: Refrain from drinking and driving. Provide teens a ride home or cab fare if they or their driver have been drinking. Sign written agreements with your kids that outline safe driving rules.

Health care professionals should educate teens and parents about substance use and driving. Screening kids for dangerous habits is important, too. Communities can help by promoting awareness of the problem and strictly enforcing driving restrictions and drinking ages.

Teens must be committed to safety and to making good choices. That means not just staying away from alcohol themselves, but also refusing rides from others who’ve been drinking.

Like finding your way across town, helping your teen steer clear of drinking and driving just takes a good road map.