The PAX index, calculated each year by the “Professional Autocross” people (whoever they are) is a commonly used handicapping system for comparing times of cars which are not in the same class. The index is composed of data from across the country, and tries to take the driver out of the equation and compare only the cars.

These indices are based on cars prepared to the limit of the rules and driven by top drivers. (RLS to see the current year’s indices, if your region uses them)

The index is multiplied against your run time to provide the time you would have had if you had been in an A-Modified car. It is interesting to compare the index of one class to another to see how much time you should gain if you prepared your car to, for instance, Street Prepared rules. Look in the rule-book to find out where your car would be if you made modifications. You can also see that alphabetically, higher cars are not necessarily faster.