What is the test for a driver who fails to stop at the scene of an emergency call-out?

[14] In examining the text of paragraph 159(1)(a) of the H.T.A., I find that the language contained therein is not sufficiently precise so as to properly classify the offence as one of absolute liability. In my view, the phrase “shall immediately bring such vehicle to a standstill, as near as is practicable to the right-hand curb or edge of the roadway and parallel therewith and clear of any intersection”, contained within paragraph (a) of the subsection, may be interpreted as establishing an imprecise standard in respect of how a driver would be expected stop his/her vehicle upon the approach of an emergency vehicle. I am of the view that the language used to create the offence, in particular the imprecise language used in the aforesaid phrase can, as stated by the Court in Regina v. Raham, supra., “reasonably admit of a due diligence defence”.