Expounding upon Alan and Kornholio's correct posts...
If you guys are being serious....
2015 Vehicle Code definitions from DMV:
Trailer
A “trailer” is a vehicle designed for carrying
persons or property on its own structure and for being drawn
by a motor vehicle and so constructed that no part of its weight
rests upon any other vehicle. As used in Division 15
(commencing with Section 35000), “trailer” includes a
semitrailer when used in conjunction with an auxiliary dolly,
if the auxiliary dolly is of a type constructed to replace the
function of the drawbar and the front axle or axles of a trailer.
Amended Ch. 542, Stats. 1984. Effective January 1, 1985.
Motorcycle
(a) A “motorcycle” is a motor vehicle having a
seat or saddle for the use of the rider, designed to travel on not
more than three wheels in contact with the ground.
I gather then, that since side cars/trikes rest weight upon the vehicle, they therefore are not trailers, and fully meet criteria of motorcyles and then, are...motorcycles.
Also...
Bridge Toll info:
MULTI-AXLE VEHICLES
All Bridges
Effective July 1, 2012:
3 axles regular toll of $5.00 times 3 axles - $15.00
4 axles regular toll of $5.00 times 4 axles - $20.00
5 axles regular toll of $5.00 times 5 axles - $25.00
6 axles regular toll of $5.00 times 6 axles - $30.00
7 axles or more regular toll of $5.00 times 7 axles - $35.00
Toll is based on the total number of axles on the roadway in a vehicle combination. Tolls that vary by time of day are determined by the time clock or time keeping device at the toll collection point.
Motorcycles are classified as 2 axle vehicles.
Tolls are collected eastbound only on Antioch Bridge, Benicia-Martinez Bridge, and Carquinez Bridge and westbound only on Dumbarton Bridge, Richmond-San Rafael Bridge, San Francisco-Oakland Bay Bridge, and San Mateo-Hayward Bridge.
Bold Added. Well, since CVC motorcycles are anything up to 3 wheels that bear the weight of the vehicle, it seems side cars/trikes should ONLY pay regular motorcycle tolls. Motorcyles being counted as having 2 axles by bridge toll authority by their definition. Only when towing should they be bumped up to 3 axle toll. I guess a better way to say it is, all motorcycles have 2 axles...some have 3 wheels.