A new AAA study outlines dangerous driving mistakes teenagers make and how to prevent them. There were over 14,000 fatal traffic accidents involving teen drivers over the last five years. Two-thirds of the people who are injured or killed are not the teen drivers. More than 4,200 of those fatal crashes involved speeding, according to AAA. The organization held a study of driving instructors. It found speeding, distraction, and poor visual scanning are the top three mistakes for new teenage drivers.