TRENTON, N.J. (AP) — New Jersey teens opposed to the nation’s first state law requiring young drivers to display license plate decals that identify them as inexperienced have gained support for their cause from several state lawmakers and a national youth rights advocacy group.

The statute known as Kyleigh’s Law takes effect Saturday. It requires New Jersey drivers ages 16 to 20 to have a $4 pair of detachable fluorescent red decals on their front and rear license plates during a yearlong provisional license period. Failure to do so could result in a $100 fine.

The decals are intended to help police enforce licensing restrictions on first-time drivers, which limit the number of passengers they can carry and the hours they can drive. They gradually earn full driving privileges under the state’s Graduated Driver License program.

The law was named for Kyleigh D’Alessio, a 16-year-old central New Jersey high school student who was killed in 2006 while riding in a vehicle driven by another teen. Democratic Gov. Jon Corzine signed the law last year.

Opponents claim the law is well intentioned but won’t improve safety, will subject motorists to nuisance traffic stops and might entice criminals to target young drivers.

‘‘Kyleigh’s Law doesn’t prevent car crashes,’’ said Hal Levy, a 20-year-old college freshman and member of the board of the National Youth Rights Association. ‘‘It’s more of a feel-good law, at the expense of young people. We oppose the profiling by police and the stalking.’’

Levy, a Livingston resident, said he will hold off on buying the decals to set an example until the law can be repealed. He also has less than a month until he turns 21.

Gov. Chris Christie said his 16-year-old son, who has yet to get his provisional license, has also complained about the requirement.

‘‘I see upsides and downsides to it,’’ Christie said. ‘‘If I were governor at the time, I don’t know if I would have gone that route’’ and signed the bill.

The Republican governor said he will enforce it and he’s even open to changing it if it seems ineffective.

A few state Assembly Republicans plan to introduce a bill in May that would rescind the decal requirement.

Meanwhile, the youth rights advocacy group is encouraging all drivers, regardless of age, to obtain the decals and display them even if they aren’t required to as a way to thwart the law.

State highway safety officials doubt such tactics will catch on.

‘‘If you don’t mind being stopped when you are out at 2 in the morning, more power to you,’’ said Pam Fischer, director of the New Jersey Division of Highway Traffic Safety. ‘‘In order for the Graduated Driver License to be enforced, police have to be able to spot provisional drivers.’’

Republican Assembly member Charlotte Vandervalk of Bergen, one of three sponsors of a bill to rescind the decal requirement, received letters from constituents who think the law poses a safety threat for teenage girls.

‘‘It causes unintended safety concerns,’’ Vandervalk said.

But Mike Horan, a spokesman for the Motor Vehicle Commission, which issues the decals, disputed that argument.

‘‘A predator is not going to wait until this decal is displayed to do harm,’’ Horan said.

As of Friday, the agency had sold nearly 32,000 sets of decals. It expects to sell about 500,000 in the law’s first year.

Nearly 3,500 teens in the United States aged 15 to 19 were killed in motor vehicle accidents in 2008, and more than 350,000 were treated for injuries suffered in crashes, according the Centers for Disease Control and Prevention.

The National Highway Traffic Safety Administration says 46 states and the District of Columbia have graduated license programs. The agency said the programs have accounted for a substantial decline in teenage vehicle crashes — between 20 and 50 percent.