The law about scales is tricky (where it isn't).
Legally all commercial vehicles should pull to scales in CA. Bare in mind you can register station wagon as commercial vehicle.
My dually is registered as RV (DMV has special category for it) and I ignored scales with utility bed and ignore them now.
In the past, driving empty F450 flatbed I ignored scales as well and nobody was chasing me.
Pulling equipment trailer I stop at scales and almost all the time got full inspection as trailers break-away brake systems are red flags for DOT.
Than lot of CA weigh stations have signs "no pickups"
Now a quiz for CA pickup owners >>> what is definition of pickup in the state?
