"During the tests, saliva samples were collected through random stops and roadblocks, with 80 per cent taken from drivers and 20 per cent from passengers. About 15 per cent of the tests registered a positive drug reading, Public Safety said."

Which raises two questions, for me:

1) On what basis were they testing so many passengers?  There's no law against being an impaired passenger.

2) What percentage of those 15% positive tests turned out to be accurate?  How does this device compare to rolling a die and calling every '1' a positive result?