The PAX index was developed by Rick Ruth and reflects study of results from well over 500 nationwide Solo events. The below information is sourced from the official PAX webpage.
| Category | Class | Multiplier (1999) | Multiplier (1998) | Difference |
|---|---|---|---|---|
| Stock | A Stock | 0.815 | 0.825 | -0.01 |
| Stock | B Stock | 0.811 | 0.819 | -0.008 |
| Stock | C Stock | 0.802 | 0.809 | -0.007 |
| Stock | D Stock | 0.800 | 0.804 | -0.004 |
| Stock | E Stock | 0.786 | 0.791 | -0.005 |
| Stock | F Stock | 0.807 | 0.815 | -0.008 |
| Stock | G Stock | 0.788 | 0.794 | -0.006 |
| Stock | H Stock | 0.785 | 0.788 | -0.003 |
| Stock | Super Stock | 0.825 | 0 | |
| Stock | Super Stock | 0.812 | 0 | |
| Stock | Super Stock | 0.789 | 0.829 | -0.04 |
| Stock | Super Stock | 0.830 | 0.839 | -0.009 |
| Street Prepared | A Street Prepared | 0.852 | 0.859 | -0.007 |
| Street Prepared | B Street Prepared | 0.846 | 0.853 | -0.007 |
| Street Prepared | C Street Prepared | 0.844 | 0.850 | -0.006 |
| Street Prepared | D Street Prepared | 0.820 | 0.832 | -0.012 |
| Street Prepared | E Street Prepared | 0.822 | 0.830 | -0.008 |
| Prepared | A Prepared | 0.871 | 0.884 | -0.013 |
| Prepared | B Prepared | 0.874 | 0.882 | -0.008 |
| Prepared | C Prepared | 0.857 | 0.863 | -0.006 |
| Prepared | D Prepared | 0.853 | 0.861 | -0.008 |
| Prepared | E Prepared | 0.872 | 0.878 | -0.006 |
| Modified | A Modified | 1.000 | 1.000 | 0 |
| Modified | B Modified | 0.955 | 0.967 | -0.012 |
| Modified | C Modified | 0.925 | 0.935 | -0.01 |
| Modified | D Modified | 0.900 | 0.908 | -0.008 |
| Modified | E Modified | 0.909 | 0.917 | -0.008 |
| Modified | F Modified | 0.904 | 0.905 | -0.001 |
| Formula | Formula 125 | 0.950 | 0.965 | -0.015 |
| Category | Class | Multiplier (1999) | Multiplier (1998) | Difference |
Every year, many national champions and trophy winners choose Autocross Digits for their numbers and classes. A full list can be seen in our Hall of Fame.
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Written by Rocky Entriken, this is the record book of 52 years of the Sports Car Club of America's National Solo (autocross) championships from its beginning in 1973 to 2025, including a brief history of the sport and the championship. It includes the final placing of every driver who has ever competed in the annual event.
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