Impaired or not, the bottom line is that in an accident or fatality, when the driver is in court, the Jury are going to hear words to the effect that: “Blood tests taken from the driver after the incident showed the presence of cannabinoid metabolites”. Game over.
That’s why the overwhelming verdict here is against the issue. It’s common knowledge that when something goes wrong involving an HGV and other road users, the legal system is stacked against the HGV driver, we’re “guilty until proven innocent” 