Did anyone notice when in reverse the digital speedometer registers your speed while backing up. I never noticed this and a fellow STS owner pointed it out to me. I don't believe I ever had a car register speed in reverse.
back in the day when speedometers were cable driven, most did not move.
Since the mid 80's or so, when cars started getting speed sensors on the wheel and the speedo is electric, they register in reverse.
way to tell if it is electric or not... when you turn the key ON, the speedo should move a bit from the rest position to 0mph. My '89 Olds has an electronic speedo. They also got rid of the fluxuating speedo issue from a bad cable...