HOUSTON—Authorities were searching Thursday for a man accused of shooting a teenager during what they say was a road rage incident that took place as a family was driving home following a Houston Astros game. The 17-year-old was on life support at a hospital following the Tuesday evening shooting, according to Houston police. The teenager’s father was driving from Minute Maid Park when he exchanged hand gestures with the driver of a white, four-door Buick sedan with a sunroof, according to investigators. The 17-year-old was one of two passengers in a truck driven by his father, police said. Police allege the driver of the Buick followed the family for several miles before firing several shots at their truck at around 11 p.m. on Tuesday. The teenager was shot in the head. Authorities have not released the teen’s name, but his family in a statement to KHOU-TV identified him as David …