In times of poor weather, the race can be shortened.

The race was shortened by two laps due to rain.

From 1993 to 1995 the race was shortened to a 50-kilometer distance.

The 2009 race was shortened to 500 miles due to the recession.

On August 10, 2011, it was announced that the race would be shortened to 400 miles, beginning in 2012.

The race was shortened to its present length in 1995.

The race was shortened to a mile in 1972, and from this point it held Group 3 status.

The race was shortened to 181 laps due to rain.

The race was shortened to 2 hours in 1992.

The first 15 races were shortened 10 percent due to the 1973 oil crisis.