Jackson Whiteker doesn’t drive yet, but he’s already found a traffic law he’s willing to break: the one that bans anyone younger than 18 from talking on a cell phone while driving.

The law, passed last month, goes into effect in July and will apply to drivers such as Whiteker, who plans to get his license in February. But the Carmel High School freshman said that unless he sees it enforced vigorously, the new law doesn’t provide much incentive to hang up while he drives.

“I don’t think (police) will be able to tell how old you are, and I don’t think they’ll be pulling people over for talking while driving,” said Whiteker, 15. “I will follow the law only if it can be enforced.”

Other teens appear to share Whiteker’s attitude, according to studies and experts. That brings a new challenge for driving-safety advocates who, after working four years to get the law passed, are campaigning to get teens to follow it by making parents and young drivers aware of the law before the school year ends.

“Teens have to know about it and why it’s good,” said Ryan Klitzsch, division director of traffic safety at the Indiana Criminal Justice Institute. “Then you have to have parents as the enforcement side of it.”

Nationwide, 21 states ban cell phone use for novice drivers, and 11 states restrict them from text messaging while driving. Five states forbid all drivers from using handheld cell phones but permit hands-free devices.

Indiana’s new law, which also extends curfew hours for new drivers and ups the age requirement for getting a license, bans use of all telecommunications devices for teen drivers. The law makes it a primary offense, meaning police can pull teens over for the violation.

Since the law passed, advocates have been circulating literature about it to high schools and driving schools.

But the limited research examining the effect of laws banning cell phones while driving has revealed they do little to change drivers’ behavior. A study released in June by the Insurance Institute for Highway Safety showed the percentage of teens observed using cell phones in North Carolina increased from 11 percent to 12 percent five months after a ban went into effect in the state.

“Laws are ineffective on cell phone use,” said Jonathan Adkins, a spokesman for the Governors Highway Safety Association. “If you have a law people don’t think is enforced, they don’t respect it.”

Sgt. Anthony Emery, a spokesman for the Indiana State Police in Indianapolis, said state troopers will enforce the violation when they see it, but they won’t target it, because they have more serious violations to address.

“We’re not going to run out and be looking for teen drivers on the phone,” Emery said. “It’s a priority thing. If it’s a slow day, it might be at the top of the priority list.”

Backers of the law, though, say the purpose of the law isn’t to ticket teens but to give parents leverage to enforce their own rules about safe driving.

Rep. Peggy Welch, D-Bloomington, who sponsored the legislation in the Indiana House of Representatives, said that since the law passed, she’s been approached by parents who have thanked her.

“It helps parents say, ‘This isn’t just one of my rules, but something the law believes is important,’ " Welch said.

In fact, it could be parental authority, not state law, that squelches Whiteker’s plans.

Whiteker’s parents have encouraged his 19-year-old sister to avoid using her phone while driving, and they’ll do the same for their son.

“To me it doesn’t matter whether we have a state law or not,” said Greg Whiteker, Jackson’s father. “We have a family rule.”