The UK's premier poo-powered bus, the "Bus Hound," has broken the land speed record for a regular service bus. The bus, which is operated by Reading Buses, hit a confirmed top speed of 76.785mph (123.5kph) around the Millbrook Proving Ground in Bedfordshire.

The bus, which is powered by biomethane derived from cow manure, would usually be limited to 56mph. Reading Buses performed some "minor tweaks" to allow for the higher top speed (presumably some suspension tweaks and removal of the speed limiter), but otherwise it's a standard bus that would normally putter around the streets of Reading. The bus is painted black and white in a pattern that is reminiscent of the Friesian cows used for milk production in the UK.

"It was an impressive sight as it swept by on the track," Reading Buses' chief engineer John Bickerton told the BBC. "It sounded like a Vulcan bomber—the aerodynamics aren't designed for going 80mph."

The Bus Hound (which is a tongue-in-cheek homage to Bloodhound SSC) is powered by biomethane, which is produced by anaerobic digestion of cow manure by bacteria in a bioreactor. The biomethane is then compressed, liquefied, and stored in seven tanks fixed to the inside of the bus's roof. Liquefied biomethane is very similar to compressed natural gas (CNG), which can be used with slightly modified internal combustion engines.

Biomethane, of course, is seen as a greener alternative to either gasoline or natural gas; not only are you leaving those fossil fuels in the ground, you're also combusting methane that would've otherwise ended up as an atmospheric greenhouse gas.

"Most importantly, we wanted to get the image of bus transport away from being dirty, smelly, and slow," Bickerton said. "We're modern, fast, and at the cutting edge of innovation."

While the Bus Hound is powered by cow manure, another bus in the UK, operated by GENeco, is actually powered by human poop. Clearly, the stage is now set for some kind of poo bus showdown. Can cow manure hold onto the speed record, or will human poop squeeze out ahead?