The use of license plate decals for drivers with learner permits doesn't seem to have reduced their crash rate in New Jersey, the first US state to introduce the regulation, finds research published online in the journal Injury Prevention.
New Jersey introduced the requirement for license plate decals--red reflective signage advising that the person behind the wheel is still a novice driver--as part of its Graduated Driver Licensing (GDL) policy for drivers under 21 in 2010. The regulation covered both drivers with learner permits and those with intermediate licenses.
New Jersey was the first US state to adopt this strategy, with the aim of making young novice drivers more readily identifiable to the police, and so promote safer driving and greater compliance with the restrictions imposed by GDL.
While decal provisions have existed in international jurisdictions for decades, they have never been properly evaluated for their effectiveness.
The researchers therefore used information from the state's driver licensing database and police-reported crash database to estimate the monthly incident rates for each permitted driver under the age of 21 from January 2006 to June 2012 in New Jersey.
The analysis showed that GDL decal provision was not associated with a change in crash rates among New Jersey drivers with learner permits or with traffic citations for violation of the state's GDL restrictions.
The GDL citation rate was 2 per 10,000 drivers both before and after the introduction of the decal regulation, after taking account of age, gender, calendar month and the price of gas.
The researchers' previous study indicated a significant 9.5% decrease in the crash rates of young intermediate licensed drivers in the two years after the introduction of the regulation.
The researchers speculate that the likely reason for the new findings is that compliance with passenger and nighttime restrictions is already very high and crash rates already very low among drivers with learner permits--who must be supervised by a licensed adult driver--leaving little room for interventions to have a substantial impact on crash rates.
On the other hand, the requirement for the use of decals during the learner permit phase may help establish safer driving behaviours and/or contribute to compliance with the decal, GDL provisions, and other traffic safety laws in the intermediate phase, they say.
Several US states have or are currently developing legislation for decal provisions, and decals were a recommended provision in a recently proposed beefed up US GDL framework, they add.