I usually keep my trawling to the United States patent system, and I worry that might give people the impression that we are a society that is particularly prone to goofy inventions. I hope that today’s sample from the UK will help you understand that invention knows no borders, neither of geography nor of good sense.
Let me therefore introduce to you the Animal Powered Drive Means:

The concept is that you strap a horse into a harness over a treadmill. The driver can then use gearing to vary the speed of the vehicle. The big selling point appears to be that the horse can walk on a smooth, clean surface and so reduce the risk of injury.
While I’m sure this would have been a fascinating innovation over horse-drawn carriages in the 1800s, its utility when it was filed in 1979 is less apparent. I was able to find some contemporary reporting in the July 16, 1981 issue of New Scientist, but the brief article had no deeper insight than what was available in the body of the patent itself.

Unfortunately, the lack of further reporting means that the horsebus probably never met with commercial success. Having seen horses in action, I am not sure the design adequately accounts for the inevitable pile of horse poop that will accumulate at the back of the conveyor belt, nor how to prevent it from gumming up the mechanism. Maybe if the inventor had managed to solve that problem, we’d see one-horsepower buses plodding around England to this day!
UPDATE May 10, 2022:
A reader informed me that someone has actually tried to make this thing, or something very like it. Back in 2007, a “company” in Dubai named Fleethorse started promoting an internally horse-powered vehicle called the NaturBus. Naturally their website no longer exists, but the Wayback Machine did capture it. Also, here are some links to reporting on the NaturBus and a video that archive.org also thankfully managed to save:
Engadget – Fleethorse’s Naturcar: sometimes one horsepower is all you need
Autoblog – Hybrid concept has only one horse
Fleethorse – Concept video