Tip - Collision Course

As Elizabeth Dinunzio neared the end of her sunny midafternoon run last April, she turned onto Old Emmitsburg Road, a two-lane county road that is popular with runners living outside the Maryland city of Frederick. She was less than a half mile from the campus of Mount Saint Mary's University, where in a couple of weeks she was expected to graduate magna cum laude and go on to teach high school Spanish. DiNunzio was even more excited, though, about running her first 26.2-miler, the Pittsburgh Marathon, in five days.At 22, she had no reason to doubt the road ahead of her.