Sonic Adventure 2: Battle Easter Egg - Street Sign References

In Radical Highway, you may have noticed some street signs hanging above the course.

Amigo: A reference to Samba De Amigo, another popular SEGA franchise.

Freedom: A refernece to Planet Freedom, from either the Fleetway Sonic comic series or the old Sonic cartoons (SatAM/Sonic Underground), can't remember which.