Cannibis can be in your system for weeks or months, so take the authority reports that the accident was caused by cannabis intoxication with a grain of salt, and assume that absent other evidence it might be that the user in this case wasn’t high at the time.

I’m not saying this to say no accidents has been caused by cannibis, but that there’s currently no way to tell current level of cannabis intoxication. Authorities will use the lack of nuance in their favor.

> Cannibis can be in your system for weeks or months

No.

You are confusing the tests for cannabis metabolites (that can tell if you smoked weeks ago) to tests for THC, the substance that gets you stoned and leaves the bloodstream as you sober up.

A driving impairment test will test for THC, not metabolites. Nobody cares if you smoked last week, only if you are under the influence when driving.

In the UK, having 2ug / litre of THC in the blood is a drug-driving offence. At a minimum you will loose your licence for 1 year.

https://www.majlaw.co.uk/offences/drug-driving/cannabis/

> 2ug / litre of THC in the blood is a drug-driving offence

So I can have up to 8ug of THC in my blood? If I took 0.1mg (100ug) of THC (and would be very NOT high in this case, as it is 1/100th of a "normal" dose) I would probably be over the limit in that case, so sure they may be able to test for THC in the blood, but the limit is so laughably low as to effectively ban cannabis users from driving.

Read the bloody link I provided!

this is probably the second-most studied thing in forensic toxicology after alcohol use.

> Cannibis can be in your system for weeks or months

and the levels of active compounds[1] in somebody recently using, vs someone months away from use look very different, and their nature will generally work to the benefit of the defendant when reviewed by a competent forensic toxicologist.

[1] - not a yes/no from shitty screening methods; that kind of information comes off of quarter-million dollar mass spectrometers. they should be able to separate all of the inactive and active compounds from each other, enumerate them and list their exact concentrations in the blood.

Show me that they could tell if I was smoking one hour ago versus one day ago? That’s the point here, I bet they can’t even reliably tell one week versus one hour. Maybe they can tell off I had only smoked several months ago, that won’t help me tomorrow if I smoke today before dinner.

> absent other evidence

Perhaps a car embedded in the second floor of a house?

A traffic collision is not evidence of inebriation, though, since people get in collisions when not inebriated. I'm talking about someone following them that saw them weaving, not holding a phone, perhaps nodding asleep, or maybe even someone saw them smoking a joint, then a just-lit joint was found at the scene.

Driving high and drunk are idiotic to equate. Not saying you can't be impaired high, but people can also drive after a joint better than anyone after equivalent alcohol intoxication.

This smells like teetotaling more than evidence-based discourse.

This is an interesting claim, or I'm reading it wrong. Wouldn't "equivalent intoxication" mean the driver in both cases equally shouldn't be behind the wheel?

Somewhat related, but I'm still curious how they test marijuana intoxication level in drivers. Is there an equivalent BAC-type test, especially considering how long weed stays in the system?

> Wouldn't "equivalent intoxication" mean the driver in both cases equally shouldn't be behind the wheel?

No, "equivalent" here is general-purpose intoxication, not something calibrated to driving. Since the effects are so different, we should expect significantly different levels of driving impairment to be likely.

What is this based on?

That the drugs work in very different ways so we shouldn't assume they have the same intoxication profile? I feel like that's basic knowledge.

For where I say we're looking at general purpose vs. driving-specific, that just seems to me like the most reasonable statement they would have been making.

I think the confusion might lie in the use of your term "equivalent intoxication" then. Especially when you then mentioned their different intoxication profiles. How exactly would you define equivalent intoxication levels in something with different intoxication profiles?

Not my term, but some kind of test might make sense, or the average of several things. I mean, how do you define intoxication levels at all? You can't just, like, measure reaction time and say you're done.

Yeah it's not easy with alcohol either. Many people have almost no impact on their cognitive abilities or reaction times with a BAC of .08, while others could be legal to drive with a .06 but shouldn't be.