weshigh

Those may be bad examples, but just a quick look at the CVC shows school buses have a section where other vehicles are not allowed to pass when they are stopped to unload. If you throw some lights and sign on your car or bike, no one is required to stop to allow you to unload. I am sure there is a section in the CVC that prohibits cars from driving in the bus only lanes.

Here is the CVC pertaining to prohibiting commercial or vehicles exceeding a max weight limit.

CVC 35701. (a) Any city, or county for a residence district, may, by ordinance, prohibit the use of a street by any commercial vehicle or by any vehicle exceeding a maximum gross weight limit, except with respect to any vehicle which is subject to Sections 1031 to 1036, inclusive, of the Public Utilities Code, and except with respect to vehicles used for the collection and transportation of garbage, rubbish, or refuse using traditionally used routes in San Diego County when the solid waste management plan prepared under Section 66780.1 of the Government Code is amended to designate each traditionally used route used for the purpose of transporting garbage, rubbish, or refuse which intersects with a local or regional arterial circulation route contained within a city or county's traffic circulation element and which provides access to a solid waste disposal site.