Fleethorse, a Dubai-based company, has designed a variety of horse-powered vehicles, like the bus shown here. These vehicles are a bit different that the carriages of days past because the horse directly propels the vehicle and charges up a motor that assists the horses. Another difference is that the horses are inside of the carriage while the people ride on the outside, which is opposite of traditional carriage, but probably for the better given that horses have the tendency to poop a lot.

High-tech monitoring equipment keeps the health of the horses in check. If the animals get tired they can take a breather and the charged motor will start up to keep the bus going at a steady speed. The vehicles are capable of traveling from 37 to 50 mph while the horses run upwards of 20 mph on the treadmill. Don't expect to see these buses racing down the track — they're intended for tourism.
— Travis Hudson

Fleethorse, via Treehugger