We already have this situation with prescription drugs. I agree it should be worked out, but failure to do so is not in itself a problem; same with prescription drugs, while there's a lot of ambiguity around when a person is under the influence, as it were, it just makes it so arrests have to be for actual occurrences. Reckless driving, or an accident caused by it. As you mention yourself, the driver ran a stop sign; all the marijuana does is add an additional offense, it's not like the driver walks scot free because the system is unable to respond to his drug usage.

Legal limits for alcohol are pretty arbitrary. Someone who's driving way over the limit isn't going to get caught unless they're driving dangerously anyway.

> unless they're driving dangerously anyway

"Driving dangerously" should be the metric. Not whether your body contains chocolate milk, weed, alcohol, oxycotin, aspirin, or whatever.

It's a pretty lousy 'after the facts' metric though. Driving dangerously is generally not visible until you're faced with a situation that requires all your attention, and then it's probably too late.

Too many people under the influence of alcohol or drugs are under the impression that because they can drive in a straight line and stop at red lights they are not dangerous and are being 'careful' and 'responsible', yet their judgement and reflexes are nonetheless impaired and this makes them dangerous.

Besides, you can't reasonably equate aspirin and chocolate to the dramatic effects that even a moderate amount of weed and alcohol have on your attention and brain response.

I'm all for the decriminalisation of drugs but I'm also in favour of zero tolerance if you choose to get behind the wheel.

There's apparently a breathalyzer in development[0] that can detect use within the past two hours.

[0] http://www.ctvnews.ca/canada/thc-breathalyzer-could-help-pol...

if it works, that would solve the problem of detection.

>> But there are some real issues to be worked out, as someone who had a friend sent to hospital after being hit by a stoned driver who blew through a stop sign. Whats the legal limit?

Sorry that happened to your friend. Was it proven that the driver was stoned? If so I'm guessing they have an accurate way to measure it. Either way this is always going to be a problem. Look at the number of people killed by drunk drivers. The only solution is harsh prison sentences imo. Some people, willing to take the risk of DWI, disregard the danger they pose to others and if they can't understand that they should be severely punished. DWI shouldn't just lose you your license and get you probation. The punishment should be much more severe.

As for your question on the legal limit - there shouldn't be one. If you get in the car you should not have had any marijuana in the last 24 hours.

The problem is the studies that show that MJ use is far less of an impact on driving than talking on a phone... The paranoia over stoned drivers is a little high (no pun intended)

Not saying it should be ignored as an issue all together, but it seems to be the last issue the opposition can attach itself to and sound sane, and its getting a little carried away.

With self driving cars on the horizon it will at some point become a moot point.

Even if that's true the drugs effect is different on each person and the amount you take will vary the effect it has on your driving ability. A couple of puffs probably won't make a difference. But you can also take enough that it's hard to even get out of a chair. The easiest solution and one that should appease everyone would be a total ban on driving within 12/24 hours of last taking marijuana imo.

I get that... its a legitimate concern, as I said. However, its no more legitimate than the other 100s of prescription drugs that can cause drowsiness or slowed reaction time. Or driving with the flu, or driving tired.

Thats the point - there are literally 100s of other ways to be just as (if not more) impaired while driving and be completely legal. We don't parade those issues around (namely because the big pharma companies would like people to not realize just how impairing their products are)

The difference is that there is a large enough group opposed to legalization that they make this issue a primary one in their fight against legalization and blow it vastly out of proportion to the actual scale of the problem.

That's true with alcohol, too, though, it effects people differently. .08 was basically just resolving legal ambiguity by picking a reasonable BAC; it's not like at .079 you can operate a car safely but at .08 you're a danger to everyone on the road.

You can actually be arrested for an 'OUI' in some states, an Operating Under the Influence, for when you are clearly impaired, but fall below the legal cutoff for a DUI. This would likely necessitate being the same sort of thing, a legal recognition that you were driving recklessly, and you exhibit the signs of recent marijuana usage (or if we have some way of actually measuring it, then that too).

12/24 hours?? Have you ever smoked? I'd say the effects mostly wear off within 2 hours...

A total ban on driving for 24 hours is scientifically unsound, and would only play into fearmongers' hands who want more legally dubious checkpoints and reasons to do intrusive tests on drivers.

That only applies to a point. I've been high enough that I had trouble walking (fun with poorly calibrated edibles...); driving would have been impossible. Luckily 'couch-lock' tends to limit how much mischief people get up to while heroically high.

There is no reliable way to chemically measure intoxication from marijuana. All the tests show is the presence of THC in the system. Hair tests can detect use as far back as 6 months, urine tests for 3 weeks, blood tests for 72 hours (typically used in accident investigations). Saliva tests, having a shorter duration of ~12 hours would be more ideal, but have an effectiveness cutoff of 50ng. The current legal limit in CO and WA is 5ng.

All that said, there's little correlation between the amount of THC in one's system and the level of intoxication. A chronic user (no pun intended) will have a much higher concentration of THC in their system and be affected less by it as compared to say, a tourist coming in and trying it for the first time in 20 years.

Lots of marijuana activists claim that driving while high does not impair your driving ability. Anyone who's ever been extremely stoned knows that even basic tasks like walking or talking are difficult, let alone driving.

I don't really mind a nearly-zero-tolerance policy for driving while on any kind of drug. Some people are way more tolerant to weed than others, and may be nearly sober even with a THC concentration that makes someone else couchlocked, but I think it's better to err on the side of caution.

> Lots of marijuana activists claim that driving while high does not impair your driving ability.

[citation needed], as I could be considered one and believe it should be handled similar to DUI, and I've never met another "marijuana activist" that thought differently.

The risk of driving after using marijuana is comparable to the risk of driving after using penicillin, which isn't illegal. Furthermore, the risk is far less than the risk of driving at .08, which is legal in most states. While I'm not advocating that people drive while stoned, it's not clear that there is a legal problem that needs to be solved.

> The risk of driving after using marijuana is comparable to the risk of driving after using penicillin, which isn't illegal.

[citation needed]

> Furthermore, the risk is far less than the risk of driving at .08

[citation needed], again

> which is legal in most states.

No, driving at or above BAC 0.08 regardless of impairment is illegal in all 50 states, and in most states driving with any impairment due to alcohol is also illegal (though a lesser offense) even if the BAC is below 0.08.

Instead of saying [citation needed], why don't you just Google it? For reference:

http://norml.org/news/2014/04/03/study-higher-thcblood-level...

And your point about .08 being illegal is pedantic. Driving at .0799 would be legal, and the risk is identical.

> The risk of driving after using marijuana is comparable to the risk of driving after using penicillin

Source? I would drive in neither case, but I certainly feel far more able to drive after a penicillin than after a few drags off a joint.

Marijuana delays reaction time. Does penicillin?

benadryl does. And nyquill. Allegra and claritin can as well (though to a lesser degree). thats not mentioning the 100s of prescription drugs that do. None of them need a roadside test, why does MJ?

I've got to query this, I don't believe antibiotics like penicillin cause any motor/visual impairment

Some antibiotics may cause problems. Quoting from http://www.drugs.com/cdi/amoxicillin.html :

> Amoxicillin may cause dizziness. This effect may be worse if you take it with alcohol or certain medicines. Use amoxicillin with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.

That said, I can find nothing similar for penicillin. Eg, it's not listed in the "impressive list of drugs [which] may cause vertigo or dizziness" at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3853661/ , though several other antibiotics are listed.

Antibiotics and other medication can destroy your hearing. Common anti anxiety medications effect your sense of balance to the point falling.

I don't agree with the GP however. There are significant differences in effect between the strains of MJ that it isn't rational to make statements like the GP.

http://www.m.webmd.com/a-to-z-guides/tc/medicines-that-cause... http://www.drugs.com/clonazepam.html

Citation definitely needed. I don't recall feeling the slightest bit impaired after taking penicillin.

Driving stoned is NOT fun. Physics feel all weird. I don't recommend it. It is scary.