Section 128(13) of the Highway Traffic Act provides that speed limits do not apply to police department vehicles used in the lawful performance of a police officer’s duties. If an officer is in the lawful performance of their police duties, this provision exempts police officers from speed limits, but not from criminal offences such as dangerous driving [FN].

R. v. Romano, 2017 ONCA 837, at para. 89.

Highway Traffic Act, RSO 1990, c H.8.
Fire department vehicles and police vehicles

128(13) The speed limits prescribed under this section or any regulation or by-law passed under this section do not apply to,(a) a fire department vehicle while proceeding to a fire or responding to, but not returning from, a fire alarm or other emergency call;(b) a police department vehicle being used in the lawful performance of a police officer’s duties; or (c) an ambulance while responding to an emergency call or being used to transport a patient or injured person in an emergency situation.  

[FN] To establish the mens rea of dangerous driving the Crown must prove that the manner of driving “was a marked departure from the standard of care that a reasonable person would observe in the accused’s circumstances”.  In applying this “modified objective test” in which the “accused’s circumstances” are relevant, the status of the accused as an on-duty police officer acting in the course of his duties must be considered (Romano, at para. 87).  The question becomes: was the manner of the officer’s driving a marked departure from the standard of care that a reasonable on-duty police office would observe in the circumstances.  Obviously, driving at an excessive rate of speed may be a relevant consideration within that standard of care analysis.