San Diego used to be a place where a lot of racing was going on, it's got the right weather, proximity to Los Angeles celebs, etc... but must have become too expensive and unwelcome to racing businesses to be viewed as having any future in racing

There used to be a lot of drag racing and road racing... even vintage racing. It's all gone now. 

Carlsbad Drag Strip, Torrey Pines, Coronado Speed Fest, racing at the Del Mar Fairgrounds (Carroll Shelby raced there) they're all gone. Of course, it could also be a problem related to overcrowding residential neighborhoods that are anti noise. 

To get a look at the many race venues, and some of the famous people involved,

 see http://sandiegoracingmuseum.weebly.com/

https://www.goodingco.com/vehicle/1955-torrey-pines-road-races-1st-place-badge-contestant-badge-and-mobil-oil-fob/

https://www.goodingco.com/vehicle/1956-cscc-torrey-pines-road-races-program-pit-pass-and-medallion/

https://www.goodingco.com/auction/realized/phil-hill-collection-life-in-racing/