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If the thought of your teenager sitting behind the wheel of a car scares you to death, it doesn't mean you're overreacting. Based on traffic statistics, your fears for your child's safety are well-founded. That's why it's important for parents to do everything they can to help teens become skilled and careful drivers.

Car accidents are the leading cause of death for teens in America, accounting for more than one in three deaths in this age group, according to the Centers for Disease Control and Prevention.

In 2009, an average of eight teens ages 16 to 19 died each day from car accident injuries. These young drivers are four times more likely than older drivers to crash for each mile driven. That's why having a teenager on your policy can greatly increase your auto insurance rates.

Easily distracted

Greg Haberman, the owner of Teen Driving School in San Diego, notes that teenagers are quick learners and often master the fundamentals of driving very quickly. Their biggest challenge is concentrating. Most young drivers are easily distracted, particularly in their early months of driving.

"They are preoccupied by other things than traffic: their CD players, the radio station, cellphones," he says. "They are not focused on the street."

The good news is that teens can be schooled to be good drivers who avoid accidents and help hold down their family's car insurance quotes. What they need is strong parental involvement and adequate supervised time behind the wheel. As a parent, you shouldn't be reluctant to enforce strict rules about safe driving. Be prepared to confiscate the keys, if necessary. Let your teen know that driving is a privilege he or she may lose if your guidelines aren't followed.

"If you do not feel your son or daughter is ready, do not let them drive," says Phil Berardelli, the author of the book "Safe Young Drivers: A Guide for Parents and Teens." "No one under 18 in America can drive without parental or guardian permission."

7 signs to watch for

Here are seven signs that you may need to limit or even suspend your teenager's driving privileges:

1. Too many passengers. According to the CDC, crash risks go up when teens drive with other teens. Nearly two out of three teen crash deaths that involve 16-year-old drivers happen when a new driver has one or more young passengers. Berardelli recommends allowing no passengers at all for the first few months after your child receives his or her license. "After they get the license, the first 100 days are the deadliest," he says.

2. Driving at night. Driving safely at night, when visibility is greatly diminished, requires maturity and experience. If your new teen driver is on the road after dark, that's bad news. The CDC reports that nighttime fatal-crash rates for 16-year-olds are nearly twice as high as daytime rates.

3. Using drugs or alcohol. This is a zero-tolerance matter. If you care about your teenager, do not look the other way if you find evidence of drug or alcohol use. Let your teen know he or she is free to call you in a situation where other teens are drinking and your child has no safe way to get home. In all 50 states, driving with a blood-alcohol content level at or above 0.08% is illegal. There is no acceptable blood-alcohol content level among drivers who are under the legal drinking age.

4. Calling you on the phone while they are driving. While cellphones are great for staying in touch with your kids, don't encourage them to call you while they are driving. The same goes for texting or fiddling with the car stereo system. Such distractions greatly increase the risk of accidents.

5. Driving while sleepy. If teens appear fatigued due to lack of sleep, do not allow him or her to drive. Encourage your child to get enough rest. To set a good example, aim to get eight hours of sleep each night yourself.

6. Not wearing a seat belt. It's true that you can't always monitor you teenager's driving habits, but this is one rule you must stress. Wearing a seat belt greatly increases your chances of avoiding serious injury during a car accident. Remind your child of this fact.

7. Too many dings. If the car your teen drives has numerous dings and scratches, it may be a sign that the driver isn't being careful. We all pick up small dents in parking lots, but if you notice a trend, ask your teen about it. Let him or her know that you're paying attention and that there are consequences for careless behavior.

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