Nhtsa Study: No Evidence Marijuana Leads To Higher Crash Risk

The National Highway Traffic Safety Administration said a 20-month survey of drivers in 2013 and 2014 found that while drinking dramatically raises the chance of a crash, there was no evidence that marijuana use is statistically significant in boosting wreck rates.

No evidence marijuana leads to higher crash risk

In fact, the NHTSA didn’t seem to be too happy about reporting their own study’s results. Check out the tortured language in their release (released on a Friday afternoon naturally): Here’s the study.



Cannabis use and Driving

"A single glass of wine will impair your driving more than smoking a joint. And under certain test conditions, the complex way alcohol and cannabis combine to affect driving behaviour suggests that someone who has taken both may drive less recklessly than a person who is simply drunk".
~ New Scientist March 2002

Crancer Study, Washington Department of Motor Vehicles
"Simulated driving scores for subjects experiencing a normal social "high" and the same subjects under control conditions are not significantly different. However, there are significantly more errors for alcohol intoxicated than for control subjects"

https://www.youtube.com/watch?v=dw1HavgoK9E
Drivers stoned on marijuana test their driving skills
So back to our drivers, and the issue many mothers are now concerned about: children having a new intoxicant to afflict their driving skills. How did the ‘impaired’ volunteers actually do? Well at a certain point, the substance had an undeniable effect on their ability to navigate a vehicle sensibly. But they all maintained surprising control, even at incredibly excessive levels of marijuana consumption. Moreover, unlike drunk drivers, they were very much aware of their state and agreed they were not on top of their game. Without over-indulging, it seems people’s critical thinking can be trusted more with a few hits than a couple of drinks.

Drug mishandling may have tainted 40,000 cases

"As someone who spent 35 years wearing a police uniform, I've come to believe that hundreds of thousands of law-enforcement officers commit felony perjury every year testifying about drug arrests."
- Joseph McNamara, former San Jose Chief of Police

NIDA and drugged driving
As usual, the only “facts” they’re interested in are those that oppose drug use in any way, and even then they’re not really concerned about whether they are actually facts.

https://www.youtube.com/watch?v=JxVuBHMKSuU
What if Police Say They Smell Marijuana?
Know your rights when dealing with police. Flex Your Rights Associate Director Scott Morgan discusses your legal rights in the event that police claim to smell marijuana.

 

the biggest danger in driving is taking your eyes off the road to watch the rearview mirror ...

 

Bad science reporting again dwr
Here’s a great way of looking at how facts get distorted by government and the media.

Landmark Study Finds Marijuana Is Not Linked to Car Crashes
USA Today nevertheless perceives a "new driving threat from dopers."

This analysis shows that the significant increased risk of crash involvement associated with THC and illegal drugs...is not found after adjusting for these demographic variables. This finding suggests that these demographic variables may have co-varied with drug use and accounted for most of the increased crash risk. For example, if the THC-positive drivers were predominantly young males, their apparent crash risk may have been related to age and gender rather than use of THC.

Further adjusting for alcohol consumption made the crash risk of cannabis consumers equal to that of drivers who tested negative for alcohol and all other drugs. In other words, the study provides no evidence that marijuana use increases crash risk. Furthermore, the authors note, that result is similar to what the best-designed previous studies have found: a small or nonexistent increase in crash risk.

NHTSA study: No evidence marijuana leads to higher crash risk dwr
The National Highway Traffic Safety Administration said a 20-month survey of drivers in 2013 and 2014 found that while drinking dramatically raises the chance of a crash, there was no evidence that marijuana use is statistically significant in boosting wreck rates.

NIDA and drugged driving dwr
As usual, the only “facts” they’re interested in are those that oppose drug use in any way, and even then they’re not really concerned about whether they are actually facts.

Evidence NHTSA leads to higher risk
"Simulated driving scores for subjects experiencing a normal social "high" and the same subjects under control conditions are not significantly different. However, there are significantly more errors for alcohol intoxicated than for control subjects"
Crancer Study, Washington Department of Motor Vehicles

Cannabis Users Are Safer Drivers Than Non-Users, New Study Shows 4.6.12
In the study, 4AIQ.org points out that the only significant effect that marijuana has on operating a motor vehicle is slower driving. 4AIQ.org says, while referencing a study by the US National Highway Transportation Safety Administration (NHTSA), that driving slower “is arguably a positive thing” and that driving under the influence of marijuana “might even make you a safer driver.” A similar study by the NHTSA shows that drivers with THC (the active ingredient in marijuana) in their system have accident responsibility rates below that of drug free drivers.

Are You Drunk Correa?
CA SB 289 Clueless Legislation

 

Ashley Halsey III again exemplifies bad journalism

Back in 2009, Ashley Halsey III, a factually lazy reporter at the Washington Post, was completely taken by the drug czar’s report about the voluntarily testing of drivers and made statements in his article like “11 percent of motorists are high” when the study had specifically stated that it only tested for presence in the blood, not whether they were high. (see How the drug czar uses lazy reporters).

When I brought this undeniable fact to Halsey’s attention, complete with direct quotes from the NHTSA study, he responded to me with this simple nonsensical insult: “Your arrogance and ignorance are impressive.”

Well, he’s at it again.

Fewer people driving drunk,but drug use on the road is rising

No. Once again, the NHTSA tested for the “presence” of drugs and specifically noted that marijuana is a problem in this regard because it can stay in the blood for so long, and that it doesn’t indicate whether the driver is “high” or “impaired.”

No. The second study did not find that smoking marijuana increased the risk of crashes. They found that, when adjusted for other demographics, marijuana did not result in any statistically significant increase in crash risk.

Lazy and ignorant (willful or not) journalism.

Jacob Sullum also found this article to be an example of bad journalism.

Interestingly, elsewhere in this same paper, that second study is discussed in a way which really reveals how big a story it really is.

Stoned drivers are a lot safer than drunk ones, new federal data show



This is the key point. The demonstration that alcohol and driving mix in a way that is radically different than other drugs.

You shouldn’t drive impaired by anything. But as a society, we shouldn’t get distracted by scare stories about roads full of dangerously stoned drivers.