(1) Designed to aid young novice drivers between the ages of 15 and 18 gain driving experience. To date they apply only to drivers under the age of 18. All states have lower blood alcohol content laws for drivers under 21, which range from none to 0.02 grams per deciliter, in contrast with 0.08 grams per deciliter for drivers over the age of 21 in most states. Includes graduated licensing as defined by the National Highway Traffic Safety Administration. Every state has a graduated licensing law.
(2) Intermediate stage; varies by state with regard to age of driver, night hours that driving is restricted, who must accompany driver during night hours and how long and what stage the restrictions are lifted. Exceptions may be made for work, school or religious activities and emergencies.
(3) Intermediate stage; limits the number of teenage passengers a young driver may have in the vehicle.
(4) Only includes states with restrictions on the use of cellphones for talking or texting by young drivers. Does not reference cellphone laws such as bans on handheld cellphones that apply to all drivers in some states.
(5) New Hampshire does not issue learners permits.
(6) Under age 16: 12 months; 16-18: 6 months.
(7) Banned for non-life threatening purposes.

Source: Insurance Institute for Highway Safety.