If parents support laws against their teenage children using cell phones while driving, they will have to do more than expect police to enforce such laws, they have to do some "enforcement" themselves.

That's clear from a study conducted by the Insurance Institute for Highway Safety.

The study took place in North Carolina, but most would probably agree that the results would be similar elsewhere.

Young people may claim to be more adept at using electronic devices than their elders - and they probably are.

But they are also less experienced at driving, thereby increasing the danger of distractions, whether those distractions are talking on a cell phone, sending text messages, eating or selecting music while driving.

The report found little difference in cell phone usage by teen drivers before and after North Carolina passed a law against use of cell phones by drivers under age 18. Illinois has a similar law.

Without better compliance, it

will be difficult to show the law having much impact on reducing accidents.

What the study did find was that among teens whose parents also restricted use of phones when their children were driving, those teens were less likely to say a typical call lasted more than 2 minutes and were less likely to have used a phone while driving on the day prior to the interview.

In other words, parents can influence their teens behavior - perhaps more than they realize.

Therefore, it is important for parents to talk about phone use while driving, remind their children of the state law and also impose their own restrictions.

That's in line with what Illinois Secretary of State Jesse White has advocated in suggesting parents set up a "contract" with their teenage children once they get a learner's permit or license.

To be effective, however, there must be penalties - imposed by parents, laws or both.

Unfortunately, parents have difficulty knowing whether their children are obeying the restrictions, just as police say it is difficult for them to enforce the law against teens.

It is difficult for police to detect phone use when hands-free devices are used or to determine a driver's age if they see a driver using a phone.

One method used in the Insurance Institute study was observing students as they left school when classes were dismissed.

It may take some "targeted enforcement" by police, as has been done to ensure seat belt compliance near schools, to drive home a message about using a cell phone while behind the wheel.

But parents are the first line of defense.

Practicing what they preach can also send an important message to young drivers in the family.