ABC News' Ryan Owens and Roger Lee report:
A horrific crash during the final lap of the Houston Grand Prix sent three-time Indianapolis 500 winnerDario Franchitti's car airborne into a fence that scattered debris into the crowd, injuring 13 people.
Franchitti, 40, was admitted awake and alert to Memorial Hermann Texas Medical Center in Houston Sunday afternoon for a concussion, spinal fracture and a fractured right ankle, according to IndyCar. Franchitti is expected to be released from the hospital later this morning.
Three of the 13 fans were also taken to Memorial Hermann Texas Medical Center but "do not appear to be in serious condition," according to a hospital spokesman. Firefighters treated most of the injured at the scene.
"Officials are investigating the incident and currently do not have further information at this time. Fan and driver safety are always a primary concern, and we will provide further details as they are available," IndyCar said in a statement.
Sunday's crash comes 10 days shy of the two-year anniversary of the death of Dan Wheldon, who crashed in Las Vegas during the IZOD IndyCar World Championship. Wheldon was killed after a 15-car wreck, and his car was launched hundreds of feet through the air and hit a fence. An autopsy concluded that Wheldon died of blunt force trauma to the head after striking a post.
After Wheldon's fatal accident, many tracks across the nation reinforced their catch fences.
Sunday's accident occurred after contact between Franchitti and Takuma Sato sent Franchitti's car launching over Sato's and into the fence. Parts and pieces from both cars flew into the grandstand, and Franchitti's badly damaged car bounced back onto the track.
"Debris flew literally inches from my head. It was a big chunk of tire but did fly inches from my head, so my family was really shaken up," fan Krista Weaver said.
Eyewitnesses say some fans were pinned under the damaged catch fence.
"The piece of fence had landed to where a lady was trapped underneath it. She was crawling underneath the fence to get out," spectator Paul Basaldua said.
Franchitti is the estranged husband of actress Ashley Judd. The two have been married for 12 years but separated in January.
"Thank you for the prayers for @dariofranchitti. I have only clothes on my back and the dogs but that's all that we need and we are on our way," the actress tweeted Sunday.
Auto racing is a fast and dangerous sport where even the spectators are at risk of injury. This past February, Kyle Larson's car went airborne into a catch fence at Daytona International Raceway during a NASCAR race, scattering wreckage and injuring 28 fans.
After that crash, a concerned Franchitti tweeted, "It's time @Indycar @Nascar other sanctioning bodies and promoters work on an alternative to catch fencing. There has to be a better solution."