A few years ago I found an Internet journal featuring a young Australian man who was trying to earn his PhD on human endurance. In order to achieve his goal he chose to ride a unicycle along the southern shore of Australia, sharing the road with the ROAD TRAINS.
As I recall he posted his progress twice each week, and I watched it faithfully. It had to be a hair-raising experience. One day his entries stopped. I still don’t know if he achieved what he set out to do, or someone ran him over before he was able to finish his documentation.
The machine he pedaled was very tall (I suppose to make himself more visible to the road traffic). It had handlebars on it and a cleat he used for mounting up. Watching a remote video of him getting started remind me of how cyclist put a Penny Farthing in motion.
Video from the Internet