They are driven by either elderly folk, hense the name, or by Obese people who are to lazy to walk and loose some weight.
2. Man, look at that lovely old couple, racing through the park knocking people down on their grannypeds.
3. When I'm old, I'ma score me a free grannyped.
4. I wish that fat chick would stop whoring that grannyped and let someone who really needs it use it.