UPDATE4: Franchitti accident update

Four-time IndyCar Series champion Dario Franchitti fractured two vertebrae, broke his right ankle and sustained a concussion when his car went airborne into a catch fence during the final lap of the Grand Prix of Houston on Sunday, with flying debris injuring 13 spectators and a series official.

Franchitti was transported to a hospital where the three-time Indianapolis 500 winner would be held overnight, and a series official was treated for minor injuries.

Houston Fire Department spokesman Ruy Lozano said 11 of the 13 injured fans were treated on site at Reliant Park. Lozano said two were taken to the hospital for treatment.