Ok, well not entirely irrelevant.
Many of these posts talk about how driving ability, that is, the ability to navigate a course while drunk or stoned, is not imparied by M.J. except at large doses (unlike alcohol which can make it hard to even go on all-fours in a straight line; I know that for a fact).
So what. Sure, alcohol significantly impairs motor skills and reaction times, but the real problem with alcohol is how it impairs judgement.
While a youngster I did drive wasted. I made an conscious effort to drive as carefully as possible so as to get home, and much more carefully than is my natural inclination.
My experience was that most people I knew lost all common sense when drunk. When they were sober, they would not do the things that I did while I was sober (some would not even ride with me to go get a burger, at least not in my race car), but while drunk they would try anything and even in the rain.
I just don't see that judgement problem with stoned people. I cannot speak from personal experience; I never did toke.
People I knew seem to pretty much drive stoned the same way they did while straight.
Those that drove like my mom when they were straight drove like my mom when they were stoned.
Those that drove like they were trying to get home to beat a diarhea attack when straight drove like that when stoned.
My crazy redneck friends didn't get mellow when they started smoking. They just turned into stoned assholes.
Anyway, I think the whole thing of doing tests on motor-skills while driving is nearly pointless.
Crashes occuring due to insufficient skills are rare compared to numb-skullery.
The real problem with people is that they get into crashes due to their poor judgement. Not watching the road ahead, fooling with the radio, reading the newspaper, fooling with their lunch, trying to one-hand text while driving where children are playing and so on.
In my observations, I don't believe that marijuana affects judgement in the way that alcohol does; it's not even close. If we are going to let people self-medicate, then I believe marijuana is a superior choice.
However, in my experience as a school teacher , something must be done to keep it (any recreational drug) out of the hands of teenagers and children. It is very obvious that many of them lack the ability to control their usage, and they seem to often become damaged in their mental abilities in a way that does not seem to happen to the adults that I knew that started later in life.
I would really really want the children problem solved. I also think that with M.J. legalized, we can do a better job of keeping it away from kids.
We used to do a much better job of keeping alcohol away from teenagers, but I think people have gven up.