WASHINGTON – Restrictions placed on young drivers over the last decade appear to be working as the number of fatal crashes involving teens is down.

The National Institutes of Health looked at laws aimed at teen drivers, some dating back more than a decade, and concluded that fatal crashes involving 16- and 17-year-olds were down between 8 and 14 percent.

States that restrict teen driving at night had a 10 percent reduction in fatal crashes.

All 50 states and D.C. have some type of restrictions on drivers under 18, including restrictions on night driving, the number of passengers in the car and more hours behind the wheel before getting a license.

The NIH study indicates the largest decrease came in states that also had mandatory seat belt laws and loss of a driver’s license for alcohol use by those under 20.

D.C., Maryland and Virginia all fit that category.

WTOP’s Hank Silverberg contributed to this report. Follow Hank and WTOP on Twitter.

(Copyright 2011 by WTOP. All Rights Reserved.)