At least 13 people were injured when Dario Franchitti's car got airborne during a last-lap crash in Sunday's IndyCar Grand Prix of Houston.Four-time IndyCar champion Dario Franchitti suffered two broken vertebrae, a fractured right ankle and a concussion in a scary crash in which his car went airborne into the catchfence during Sunday's Houston Grand Prix.Debris from his car vaulted into the stands, injuring 13 fans and an IndyCar Series official, according to the Associated Press. Two people are being treated at a local hospital.