What is the topic of the passage? [originaltext] Car crashes are the top kill

Car crashes are the top killer of American teenagers. Most of the crashes result from distracted driving—not paying attention to the road. The number one cause of distracted-driving accidents is the mobile phone. Talking on the phone or reaching for it is like drinking four beers and driving. If you’re texting while driving, you are twenty-three times more likely to get into an accident than somebody who isn’t. Reaching for a cell phone when it’s going off, you’re nine times more likely to get into an accident than normally driving. Government and private groups are using public service announcements and events to bring more attention to the problem.
    Teens are especially at risk from distracted driving—and not just because they lack experience on the roads. A research on teen brain development shows that teens don’t really have fully developed brains until they’re twenty-five years old. You put those two things together and you get a much, much higher risk. New legislation in Congress proposes to require all states to have what is called a graduated driver licensing system. Graduated means teenagers start with restrictions like on night driving and numbers of passengers. They could not get a full driver’s license until age eighteen.