Whoa!
I remember from reading the book, Wheels in His Head, what you do in that situation.
You jam your shoe in between the front tire and the fork to stop the bike. But you have to do it with some finesse so you don’t just flip the bike over on your head.
It’s a funny story about a guy who lost his brakes while cycling through the mountains. He ended up tying a bunch of sticks to a rope and dragging it on the road behind his bike so he wouldn’t go out of control, riding down the mountain.
This was a 1920’s dirt road, and he raised enough dust cloud to attract the sheriff’s attention. He promptly got arrested for operating “an illegal drag brake.”
It’s the same method they used for centuries to keep heavy wagons from rolling out of control down a hill.
It tore up the roads so bad here they just pulled the logs down on sledges with oxen, until they (Clovis Cole) built a log flume down the mountain (to Clovis.) They didn’t call it Clovis until well after they built the flume, and Mr. Cole got very wealthy.
Until then it was just a railroad spur for all the ranchers.