Crashes and Retirements
The 32 computer-controlled cars can crash at any point in the race, or retire with mechanical problems during pit-stops. In a 10-lap race, a crash causes a yellow flag to flash briefly in the top left of the screen, but all cars continue racing at full speed as if still under "green-flag" conditions. In all other race distances, yellow flags flash, cars slow down and are forbidden from passing until the incident is cleared. A crashed car typically stays on the circuit for 2-3 laps before being cleared, after which green flags flash as the leader exits turn 4, signalling that cars may continue racing. No yellow flags are shown if ones own car crashes, unless other cars hit the wreckage. During a yellow flag period, speeds are restricted to approximately 90mph (against a typical race pace of up to 230mph).
Ones own car cannot be damaged by crashes in 10-lap or 30-lap races. In the longer races, excessively hard contact with a wall, fence or another car can cause wheel and/or engine damage. It is still possible to recover to the pits after damaging one front wheel, though the car is more difficult to control. Destruction of any two tires makes recovery extremely difficult, and in most cases impossible. A very large impact, especially to the rear of the car, may cause engine damage, from which there is no recovery. After being involved in a crash, computer-controlled cars are shown as "Crashed" in the Standings screen.
Retirements may also occur due to mechanical problems. If a car suffers mechanical problems, it will pull into the pits and remain there for the rest of the race. The problem that caused the car to retire are shown on the standings screen. Possible causes of retirement are: Bearing, Clutch, CV Joint, Engine, Gearbox, Ignition, Stalled, Valve, Vibration, Radiator and Oil Leak. Again, this only applies to computer-controlled cars; the player-controlled car does not suffer from random failures.
There is the ability to blow the engine if it goes too high in revs.
Read more about this topic: Indianapolis 500: The Simulation