Memory plays tricks! The Racing Derby mentioned here doesn't ring a bell. But I do have recollection of The Rocket Speedway. Also a centrifugal force ride. But not a multiple track race. Now, this was back in the late 30's, early 40's. The location: at the foot of Balboa, north side of the street, maybe right behind the Bull Pup Ench. shop. Riders would sit, one behind the other, in a caterpillar shaped carrier. This was pulled by a motorcycle type engine, going around and around inside a bowl shaped track, maybe 30 ft. or so in diameter. As the driver gained speed, centrifugal force brought the device up the sloped wall, to a horizontal and slightly higher position. There was an observation platform with free viewing of the ride. It was very noisy, and the fumes, trapped in that big bowl of a track must have been hell for the poor driver, who had to endure it all hour after hour, every day. The ride was shut down during WWII. With rationing, it may have been a frivolous use of gasoline.
As I say, memory plays tricks. I may well be mistaken about some, or many details.