Track bicycles have fixed gears, no shifters and no brakes. As a former track bicycle racer on a velodrome it would be extremely dangerous to have brakes on the highbanks. We used backpedaling to slow. During a competition no attempt is made to slow other than coasting. Since wood tracks, usually 1/4mile long were also used for bicycle racing and later motorcycle racing was based on what worked for bicycles. Dirt racing like Flat Track there are no front brakes minimal rear brakes and no brakes are used in competition, used only to slow the bike to get into the pits.
The principle is no one can stop or slow faster than than their competitors thereby braking is not a usable tactic and simplifies the purity of the sport, then limited to speed, acceleration, tactics.
