rallying on the street.

You need to get 50 rings in a stage on each world and it will ask if you want to do a special stage. If you complete special stage , you will get chaos emerald

Evolution of Rallying - 2002 was released on:

USA: January 2002

To transform into Super Sonic, you must collect all 7 Chaos Emeralds from the Special stages. To get to a special stage, you must get 50 rings in a normal stage and jump in the big ring at the end of the stage. Note that you can go to 1 special stage per stage. So don't try to get all chaos emeralds in one stage.

rallying