California Vehicle Code
Sec. § 661


Unladen weight shall not include the following machinery, equipment or attachment which is attendant to the efficient operation of the body or vehicle:

(a)

Equipment used for loading, compacting, or unloading of refuse.

(b)

Transitmix cement equipment.

(c)

Temporary equipment used to contain or support the load which does not change the body classification.

(d)

Any camper unit that is temporarily attached to a vehicle.

(e)

Refrigeration equipment.
Source
Last accessed
Jun. 6, 2016