You really have to check your local laws, because they can be pretty different province by province or state by state, particularly when it comes to CBs and other two way radios. Take a look at Alberta for example, it's the most restrictive I've seen as far as this goes. (The "certain commercial purposes" they are referring to are truckers.)
http://www.transportation.alberta.ca/distracteddriving.htm
Looks like Alberta only went half way with the amendment. CB still no go, but VHF - Amateur Radio operators are OK to use.
Licenced Radio Amateurs have partial exemption in the Regulation as follows:
"Exempt classes of individuals
3(1) Pursuant to section 115.1(1) of the Act, an individual who
holds a radio operator certificate issued under the
Radiocommunication Act (Canada) may drive or operate a vehicle
on a highway while holding, viewing or manipulating a 2-way
radio communication device."
"
This is a pretty standard exemption in any of the no hand held device legislations passed. Amateur Radio Operators get away with a lot, another reason to get licensed
But the way it reads, if you are licensed, you can use the CB too!