A review by The New York Times of accident reports and lawsuits turned up dozens of examples of collisions in which the devices played a role. A Pennsylvania driver trying to complete a test blew so hard that he blacked out and crashed into a tree, nearly severing his left hand. Another in rural New Hampshire struck a telephone pole. And in California, a man attempting a rolling retest on a busy highway crossed the dividing line and hit another car, badly injuring a woman and killing her husband.