Four time IndyCar champion Dario Franchitti has been forced to retire due to the injuries he sustained in Houston last month.
Franchitti was launched into the fence on the final lap and sustained spinal injuries, concussion and ankle fractures.
The Scot won the IndyCar title in 2007, 2009, 2010 and 2011. He also claimed three wins at the Indianapolis 500.
Franchitti briefly flirted with Formula 1 when he tested for Jaguar in 2000, but has spent the majority of his career in the USA, racing in Champ Cars and IndyCar.
"Since my racing accident in Houston, I have been in the expert care of some of the leading doctors and nurses, all of whom have made my health, my safety and my recovery their top priority," he said.
"I am eternally grateful for the medical care I have received over the last several weeks. I'd also like to thank my family and friends for their unbelievable support."
"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."
"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."
"Racing has been my life for over 30 years and it's really tough to think that the driving side is now over. I was really looking forward to the 2014 season with Target Chip Ganassi Racing, with a goal of winning a fourth Indianapolis 500 and a fifth IndyCar Series championship."
"I'd like to thank all my fellow competitors, teammates, crew and sponsors for their incredible support over the course of this amazing ride. I'd also like to thank Hogan Racing, Team KOOL Green and Andretti Green Racing for the opportunities to compete on the racetrack, and especially Target Chip Ganassi Racing, who have become like a family to me since I joined their team back in 2008."
"I would be remiss if I didn't thank all my fans around the world. I can't thank you enough for standing by my side for all these years."
"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."
"Hopefully in time, I'll be able to continue in some off-track capacity with the IndyCar Series. I love open-wheel racing and I want to see it succeed. I'll be working with Chip to see how I can stay involved with the team, and with all the amazing friends I've made over the years at Target."