by swores | 2025-10-06 20:03:09+00:00
> Unlike alcohol for example, there's no clear dose of THC where it can be concluded beyond a reasonable doubt that the person is impaired.

Anecdotally I do think that it's more the case with THC than alcohol, but even with alcohol it's actually not so cut and dry. Two anecdotes from my life:

Me personally - when I learned to drive I was a very heavy drinker. Not "need to drink daily", but I certainly had weeks where I ended every day quite drunk. So when I started driving I bought an expensive personal breathalyser, that the company verifies calibration of before shipping and once per year after that, because while I wasn't looking to get behind the wheel right after drinking I was aware that I often drank enough to still be under the influence the next morning.

I learned that strangely, despite my having a very high tolerance for alcohol back then (like, able to drink a bottle of spirits or a few bottles of wine and still present socially as not impolitely drunk, just enjoyably buzzed), I would feel too drunk to drive before my breathalyser readings showed me above the UK limits. I verified with some disposable tests set at the (even lower) French limits, and I could pass them too while feeling too drunk to be safe driving, after ~5-8 units (a few pints of beer, or half to a whole bottle of wine). If I drank more than that then I would start blowing over the limit, but drinking that amount I would reliably be under the legal limit despite drinking enough that most people would show as way over the limit. I've no idea why, maybe my body is just weird, maybe it's related to how high a tolerance I had (though, like I said, I would be feeling too drunk to feel safe driving even if legal), or what...

Second anecdote is about the husband of a colleague I once had, back before I was a driver myself. I was at their house, we had been drinking together for a few hours, but wanted to get across town for... that's another story. So I said I'll call a taxi, but he claimed to be able to drive safely despite having had 6 or 7 large beers. I assumed it was drunken bravado and insisted no, but then his wife started backing him up and I had a lot of trust in her judgement. As it happens, a week earlier I had been at a televised esports event where all the players had been given a reaction times test using a custom built piece of software, and I had that on my laptop. So I sat him down with it, and fuck me if his reaction times while drunk weren't better than 90% of the professional gamers who'd taken the test. I still felt like I was probably making a stupid decision agreeing to get in the car with him after that, but honestly the journey was about the smoothest drive I've ever witnessed. I'm fairly sure he would have blown way over the limit if tested (unless he was weird like me, back when I knew him was before I learned about my breathalyser results), but if police had seen him drive, or talked to him, they would never have guessed he might be drunk except for the smell of beer on his breath. And it definitely wasn't just me being too drunk to realise he was driving dangerously, a couple more times in the future I got into his car sober while he has been drinking, and felt equally safe each time.

I've no idea what % of people are like me, and can be technically legal on the tests despite feeling too drunk to be safe, or like that man who could be way over the limit yet still drive safer than most sober drivers. But there's at least some people like that! Ultimately the legal limits (which let's not forget, vary from country to country) are a best effort to be a rule of thumb, they're not a perfect indicator of where the safe line is.

Edit to add: I'm sure there are far more people who drunkenly believe they can drive safely despite what they've drunk and are wrong, than there are people like that man who genuinely can drive safely having drunk a fair bit. It's very common for alcohol to give people false confidence, so please don't use my anecdote to justify drunkenly deciding to drive.