Good Enough for Police v Good Enough for Criminal Court
I agree that single point control tests and the ITP check are good practice for police. The instrument shutting down if the instrument detects an anomoly during a control test or an ITP is good design. However, these safeguards alone are not enough to ensure a scientifically reliable measurement result FOR A FORENSIC PURPOSE.
It is imperative that lawyers learn the differences between calibration of a measuring device and control tests at time of use. The latter are very helpful in screening out bad tests if the device has been properly maintained and the control test is done properly using a reliable alcohol standard.
The problem is that although a single point control test out in the field should be good enough for a police officer yes or no decision, such limited evidence of reliability is not adequate for a forensic assessment of scientific reliability. Scientific reliability is a concept central to both the Motherisk Inquiry Report and the decision of the SCC in St-Onge Lamoureux. Scientific reliability is established through recent calibration as in Jackson or recent re-calibration as in Vallentgoed combined with strict adherence to standard operating procedures i.e. good laboratory practice.