American GP - Robert Kubica has amazingly been given the all-clear to race in this weekend's US Grand Prix in Indianapolis, just two days after his horrifying crash in Canada.

The Polish BMW driver discharged himself from hospital on Monday in remarkably good shape, and was able to drive himself away.

A spokesman for his team said: "The doctors here have given him the all-clear to race."

The mandatory 'black box' aboard his destroyed single seater, however, showed a 28G impact at nearly 90 degrees, and Kubica's mild concussion means that Sebastian Vettel or Timo Glock could still be called up to take his place.

And "the peak value [of the impact] would be clearly higher than 28G, given the damage to the chassis," a BMW engineer added. Radio-Canada estimated the actual moment of impact at over 40G.

"In my day, if you had a crash like that, you would be dead, no doubt about it," Niki Lauda, who nearly died in a similar head-on crash back in 1976, said.

The 22-year-old Kubica must complete on Thursday a 25-minute examination by the FIA's doctors, where his reaction time, co-ordination and mental capacities will be compared with a 'control' test that all drivers undergo each season