New medical research helps explain why. The part of the brain that weighs risks and controls impulsive behavior isn’t yet fully developed until about age 25, according to the National Institutes of Health (O’Donnel 2). Teenagers are not mature enough to drive yet. Some may think they are mature and ready to drive because they are smart or because they act like an adult. But a teen will not be prepared because their brains not done growing. The teenage brain is also particularly vulnerable to distraction and peer pressure, and is undergoing explosive development. The front portion of the brain - which includes control of impulses, judgement, and decision-making, and the coordination of multitasking - matures deep into the 20’s, research shows (Gregory 3). This means that teens can make bad decisions while driving in a car or riding with other