You are not Fred Flintstone. You cannot stop a cartie travelling at 30mph by putting your feet on the road.

Fortunately, bike brakes are more than up to the job and can be fitted relatively easily. Many events have some form of brake test including in the pre-event inspection, so it is important to pay attention to your brakes.

The tricky part about brakes is fitting them. How you attach them is mainly controlled by how you mount your wheels. If you are using bike forks, the problem is pretty much solved for you as the forks will already have brake mounts fitted. If you are using stub axles, however, it can be rather more tricky.

Disk brakes would be the obvious choice for stub mounted wheels, but unfortunately it can be difficult to find 20" wheels that are disk compatible, meaning you will probably have to use 24" or 26" wheels. The alternative is to make a bracket to hold rim brakes. This can be tricky as the bracket will need to be strong enough to not bend under braking. The other problem with using rim brakes on stub axles is that if the stub axles bend at all - not uncommon with the standard 10mm bike axle - the brake will start to rub on the rim.