A Volkswagen of America survey cites the following four reasons for non-use of safety belts:

Setting Ground Rules for Your Teen Driver
(winter 2005)

Wrestling with a young child's car seat can challenge any parent's patience. The upside on this stage of child rearing is that you have control over your child's safety. But, when your child reaches driving age, more ominous worries emerge. Setting rules is crucial for your child's well being. Motor vehicle crashes are the leading cause of death for 15 to 20-year olds in the United States, according to the National Highway Traffic Safety Administration. Two out of three of those deaths are passengers in vehicles driven by other teens.

Driving is new to teens, and therefore they are more likely to make mistakes, use poor judgment, or have trouble reacting to sudden changes when they drive. Parents can influence their teenager's driving safety. The Insurance Institute for Highway Safety recommends that parents:

Limit Night Driving: Nighttime driving requires more skill than driving during the day and is particularly risky for teens, especially after 9 p.m. Per mile driven, the nighttime fatal crash rate for teens is almost twice as high as the daytime rate. Late night driving is usually for recreational reasons, leading to increased distraction and risk-taking.

Restrict the Number of Passengers in Your Teen's Car: Fatal crashes are more likely when other teenagers are in the car, and the risk increases with every additional passenger. Teens are more easily susceptible to peer pressure when there are more than two passengers in the car.
Insist That Your Teenager And His or Her Passengers Always Wear A Seat Belt: A Centers for Disease Control study found that 18% of male high school students rarely or never use seat belts compared with 10% of female students. Two-thirds of teenagers killed in vehicle crashes were not buckled up. It is estimated that half of all teens killed in accidents would be alive today if they had used a seat belt. Make it clear to your teen that he or she should never have more passengers than there are seat belts. Parents should emphasize the importance of seat belt use. Be sure to lead by example through consistent use of a seat belt yourself.
Talk With Your Teen About Drinking, Drug Use, Speeding, And Driving: Tell your child to call you for a ride if he or she, or another person who is driving, has been drinking alcohol or taking drugs. Alcohol and drugs impair drivers and, in part because of driving inexperience, the risk of crashing is much higher for a teenager who has used drugs or alcohol. Also, talk with your child about speeding. Teen drivers have more crashes in which speed is a factor, and many are single-car accidents caused by the driver losing control of the car.