They don't need to do 225 in an Indy car. In 1989 Nascar mandated restrictor plates (spacer over the carb) to slow the car down. Bobby Allison's car at Talladega blew a tire and took off, hitting the catch fence and spraying parts into the crowd. Many fans were injures because of the debris. Since then a few cars have got airborne, no injuries to drivers or fans.
This Indy race was the first since the repaving, the track is so smooth it's 10-12 MPH faster than the last time they raced on it in 2001 (only 24 cars that day, Sunday 34 cars).
The drivers were concerned with the speeds and made it known to officials. The President Randy Bernard was aware. Some drivers declined to race at those speeds. A.J. Allmendinger and Scott Speed were invited but said no thanks.
Irony, Dan Wheldon was the 2012 indy car of the future test driver this year. There are new advances which will keep the cars from flying thanks to Dan Wheldon's testing this past year. Will it be a perfect system? Of course not. The risk of driving these cars fast is why they race. We also have to say "When is the speed fast enough"? It shouldn't take death to change things but that's how it works. Dale Earnhardt's tragic death changed the cars they drive today. R.I.P.