By Steve Keating
AUSTIN, Texas (Reuters) - Three-time Indianapolis 500 winner Dario Franchitti announced his retirement on Thursday, just over a month after a terrifying crash left him with serious injuries.
The Scotsman said he was quitting the sport on medical advice following the heavy crash in Houston last month where he sustained spinal and head injuries.
"One month removed from the crash and based upon the expert advice of the doctors who have treated and assessed my head and spinal injuries post accident, it is their best medical opinion that I must stop racing," Franchitti said in a statement.
"They have made it very clear that the risks involved in further racing are too great and could be detrimental to my long term well-being. Based on this medical advice, I have no choice but to stop."
Franchitti, 40, suffered a fractured spine, a broken ankle and concussion after an horrific crash in Texas on Oct 6.
His car went airborne and destroyed a portion of the catch fence before spinning several times. Debris from the wreck injured several spectators after he made contact with Japanese driver Takuma Sato on the final lap.
"Racing has been my life for over 30 years and it's really tough to think that the driving side is now over," Franchitti said.
"I'll forever look back on my time racing in CART and the IndyCar Series with fond memories and the relationships I've forged in the sport will last a lifetime."
Franchitti, who was married to actress Ashley Judd for more than decade before they separated this year, won the Indy 500 in 2007, 2010 and 2012. The only drivers to have won more are AJ Foyt, Al Unser Sr and Rick Mears, who each won four times.
Franchitti also won the IndyCar Series championship four times, second only to Foyt, and won 31 Indy Car races from 265 career starts.
He is one of only five drivers to win the Indianapolis 500 and the series title in the same season more than once. He won his third Indy 500 last year, just a few months after his close friend Dan Wheldon, who won the race in 2011, was killed in a high-speed crash in Las Vegas.
"Dario Franchitti has done so much for Target Chip Ganassi Racing so it will be very disappointing to not see him in our cars next season," his team said in a statement.
"Simply put, Dario is a motorsports legend and will be sorely missed on the race track by everyone in the paddock and in the stands.
"His contributions to the sport of motor racing are too many to list but I can tell you that they go way beyond what he has done on the track."
Britain's Jenson Button, the 2009 Formula One world champion, paid tribute to Franchitti from Austin, where he is preparing for Sunday's U.S. Grand Prix.
"Dario was one of the drivers I always used to look up to as a youngster. As a human being he is a proper legend in the sport. He has achieved so much but he also carries himself so well, he's such a nice person, a lovely guy," Button said.
"It's a shame obviously that he is retiring, he's still very young at heart but he is probably doing the right thing after such a big shunt.
"Sad to see him go but I'm sure he is still going to be around the sport."
(Writing and additional reporting by Julian Linden, editing by Alan Baldwin)