I wonder if it is possible to harness a stronger-than-human animal to power a wheeled vehicle. A couch potato human can bicycle faster than 13 km/h for hours after all. This could mean that a domesticated animal could get a big speed boost by using wheels instead of legs.

The normal bicycle posture might be hard for many animals but maybe something more like a recumbent, adapted for 4 limbs since animals don't have such a big hand/leg strength imbalance...