Canadian stats are almost impossible to come by.
Check NIOSH, or the NFFF in the states for they're stats... They usually break it all down. Responding to a call, including personal vehicle does count as a LODD.
Now, my answer: In Ontario, a green light for poc FF is a courtesy light only. So the answer there is do not exceed the speed limit, and obey all traffic laws.
As far as responding in apparatus, the HTA says you can exceed the limit with ALL warning devices activated, road and weather conditions permitting, and it is safe to do so. It also says you must come to a stop before proceeding against red lights or stop signs.
They can, and will, use that "safe to do so" part against you.
My Dept has adopted a "10%" policy. Our apparatus are allowed to exceed the posted limit by 10%. Exceptions may be made depending on the situation, but otherwise we are held fairly firm to it.
Any opinions expressed are my own, and in no way reflect those of any agency, or person, other than myself.