Just enforce the laws on the books now. Pull over violators and fine them, impound the car, or arrest them depending on the severity of their violations. Impound cars that don't have properly functioning tail/brake lights. Impound cars with people using their mobile phones. Until there is a consequence in place that is enforced and "hurts" either financially or on their mobility, people won't stop.
Oh, and arrest people who don't properly restrain their children, it's called negligence.