Since I assume most players would likely have a Sprint Boost/Smoke Bomb/Throwing Knives ability set, I propose two options.
Should abilities be picked up during the race? You could get them by running through their emblem, a "random" box (like in Mario Kart), or by obtaining a certain number of bonus points.
Should each player be automatically given those (or other) abilities? Everyone has the same three abilities in a given race, and it is up to them to decide (strategically) when to activate them?