Use your own sense, bcrdukes pretty much nailed it for you. personally I travel on lions gate, Arthur laing, knight street and oak street bridge and don't have any problem at all, (Arthur laing >Oak street > knight street when going in/out Richmond) but for legal purpose:
http://www.quickscribe.bc.ca/secure/archives/475.pdf
Slow vehicles and bicycles
2.03
Concerning the Ironworkers Memorial Second Narrows, Oak Street, Knight Street,
Okanagan Lake, Annacis, East Channel, Queensborough and Pattullo bridges:
(a)
Prohibited vehicles
. – No person shall operate a vehicle during the hours of 7
a.m. to 9 a.m. and 3 p.m. to 6 p.m., Monday to Friday, inclusive, which is unable
to maintain the normal speed of traffic upon the structure or its approaches,
except vehicles engaged in emergency maintenance work.
That's all it said, Legally you are only prohibit for the above bridge at the certain time but I don't know how they define normal speed of traffic.