> Even if the driver had smoked cannabis one minute before the traffic stop, the driver’s blood plasma THC level would have fallen 80%-90% in the first hour after ingestion, and even more so after two and a half hours.

Can you source this claim from your front page? And if it is correct, how are you making sure the police correlate impairment with THC levels correctly?

If someone smoked 2-3 hours before driving, wouldn't even your device fail in this case? What thresholds are you using?