A graduated driver licensing (GDL) program limits high-risk driving situations for teens, says the National Highway Traffic Safety Administration (NHTSA). These programs been shown to reduce teen accidents by up to 50 percent, says the NHTSA.

While the restrictions may vary from state to state, all GDL programs have three phases, according to the III:

Stage 1, Learner's permit: This is a supervised learning period during which the student must complete road knowledge and vision tests. This phase lasts six to 12 months, depending on the driver's state, and the teen can only drive with a licensed adult in the vehicle during this time. Typically, 30-50 hours of driving experience is required before the next phase, says the Governors Highway Safety Association (GHSA).
Stage 2, Intermediate license: After completing stage 1, taking driver education training and passing a required road test, a new driver earns their intermediate license. During this stage, certain driving situations may still be restricted unless accompanied by a licensed adult. Typically, there are restrictions on nighttime driving as well as how many passengers can be in the car. The driver must also go without an accident or traffic violation for a set period of time to graduate from this stage. This stage typically lasts until the driver turns 18, says the GHSA.
Stage 3, Full license: Once the driver completes the first two stages and passes the required licensing tests, they will earn a license with full driving privileges.

No cellphone or electronic devices can be used during the first two phases of a GDL program, according to the GHSA.