Hey, that machine is driving on the wrong side of the road! Can that utility truck park like that while they fix the overhead wires? These are just two of similar questions that the public often ask. The answer is yes, as long as it is done safely.
Part three of the Motor Vehicle Act contains the driving rules like speeding, stopping at stop signs and which side of the road to drive on. Section 120 exempts persons, vehicles and other equipment while actually engaged in highway or public utility, construction or maintenance work on, under or over the surface of a highway while at the site of the work from the provisions of Part three.
This exemption is tempered by section 121. It says that the driver of a vehicle referred to in section 120 wil drive with due regard for safety, considering all the circumstances including the nature, condition and use of the highway and the amount of traffic that is or may be on it.
The Industrial Health and Safety Regulations also play a role. It requires that traffic control be provided whenever the unregulated movement of vehicular traffic is a hazard to workers. It goes on to explain what types of traffic controls may be required, and how to use them.