If you're planning to gauge your ability to drive after the office Christmas party by using a store-bought breathalyzer, your money would be better spent paying for a ride home.
A study of portable breathalyzer breathalyzers by CAA Quebec and Protégez-vous magazine indicates that the machines are all basically useless.
10 over-the-counter devices, including one sold at SAQ outlets across the province were tested and none are being recommended.
The study authors say while the most expensive machines can give accurate readings the machines must be calibrated before the first use and then once a year thereafter by sending it back to the manufacturer and paying a $50 fee.
One machine being sold at online shopping sites such as Groupon and Tuango $20 is described as producing "fanciful results".