http://news.bbc.co.uk/sport1/hi/motorsport/15330202.stm
Briton Dan Wheldon has been seriously hurt in a 15-car accident at the Las Vegas Indy 300.
Buckinghamshire-born Wheldon, 33, who won the series in 2005, was taken to the nearby University Medical Center.
Fellow driver James Hinchcliffe said: "Everyone's thoughts are with Dan right now. I can't describe the scene on the track at the time.
"It's a whole new dimension, knowing Dan flew out of here in a helicopter."
The crash coming out of turn two on the 12th lap had left Townsend Bell's car upside down.
Leeds-born James Jakes added: "There was a lot of moving around, people were moving around not holding their line and I saw a car hit outside of turn two."
Drivers Pippa Mann, JR Hildebrand and Will Power were also taken to hospital.
The crash ended Australian Power's bid to overtake Dario Franchitti and claim the series title.
Scot Franchitti secured his third straight series crown and fourth overall after Power was ruled out.
Wheldon, who had been unable to secure a full-time seat, started from the back of the field in pursuit of a $5m (£3.1m) prize offered by IndyCar to a non-series driver who could win the series finale.