Putting up a shop in CA - fire department being a pain

You will most certainly need to provide access and possibly enough area to turn at minimum, a type 3 engine around. The requirements are similar here in Oregon for new construction. To me these requirements make sense however I alaways marvel at how many rural folks I know with driveways that barely allow a 3/4 ton pickup to get turned around. Add in the fact that everyone thinks becaise they live near the forest it has to exist right up to the back door of the house and you have your hands full during a structure fire that soon becomes a wildland fire.

It's not just the West Coast that has these rules in place:

Fire Apparatus Access Roads | NFPA

When I lived in WI the local FD brought an engine in to fight a fire at a house adjacent to a church. The engine damaged the asphalt parking lot of the church and it sparked a debate of culpability.

Was it the land owner's responsibility to provide unabridged access for emergency services?

Should the municipality be held responsible for a damaged driveway or parking lot?

Regardless of where you stand on these matters be prepared to see more stipulations called out in building codes. Too many people have come after the utilities and emergency service providers for collateral damages incurred during an emergency.

As an example, a neighboring ranch has a large irrigation system that aggregates with several huge valves etc. This outpost happens to be unmarked at ground
level right at a tight corner one the road bordering the edge of their hay field. It was common for this irrigation to get damaged seasonally due to it's proximity to a tight corner on a narrow private road. Naturally they put all of this in within the fall line of a utility pole which is a bad idea in general. We had an unusually precipitous spring snow storm several years back and the power lines came down. Naturally the bucket truck from Pacific Power drove right over the irrigation plant (under the snow, unmarked at ground level). The land owners were outraged (-which baffles me) and proceeded to sue to utility for the repairs to the irrigation hidden in three feet of melting snow.
The point of this anecdote is to exemplify exactly why these codes are popping up.

Everything in the current world revolves around mitigating risk and proactively avoiding litigation. When the insurance companies start to say adios the severity of the situation becomes much more apparent.