A lot of people will try to tell you that they can always drive stoned and marijuana makes you a better driver rather than a worse driver, like alcohol, but that actually doesn't seem to be the case as data starts to come in from one of the first states where recreational weed is now legal. As CNN reports, via a study by the AAA Foundation for Traffic Safety, traffic fatalities in Washington State actually doubled between 2013 and 2014, the year that recreational marijuana was legalized there.

Yes, fatal accidents where pot was a factor went from 8 percent to 17 percent of the total number of traffic fatalities.

The study is bound to play a significant role in the discussions around legalization in California, which we'll be voting on in November. As the foundation's CEO Peter Kissinger tells CNN, "Washington serves as an eye-opening case study for what other states may experience with road safety after legalizing the drug."

And this is further complicated by the fact that, unlike with alcohol, there is no reliable road test for marijuana impairment or THC intoxication. California lawmakers are already mulling a bill that would mandate a roadside cheek-swab test for marijuana, cocaine, methamphetamine, and opiates, but many say this technology is totally unproven at this point. In December we heard about an Oakland startup that claimed to have pioneered a pot breathalyzer, the accuracy of which remains to be known.

Plus, no one's yet agreed on what THC level constitutes impairment, and unlike alcohol, the drug's effects on people vary widely. As the same study found — and as CBS 5 noted yesterday — six states, Colorado, Montana, Nevada, Ohio, Pennsylvania, and Washington, have set a seemingly arbitrary level of five nanograms in a person's blood as indicating marijuana impairment punishable with a DUI. But that is basically pure bullshit, as the foundation and medical experts now assert.

To wit:

The degree to which a driver is impaired by marijuana use depends a lot on the individual, the foundation said. Drivers with relatively high levels of THC in their systems might not be impaired, especially if they are regular users, while others with relatively low levels may be unsafe behind the wheel.

Some drivers may be impaired when they are stopped by police, but by the time their blood is tested they have fallen below the legal threshold because active THC dissipates rapidly. The average time to collect blood from a suspected driver is often more than two hours because taking a blood sample typically requires a warrant and transport to a police station or hospital, the foundation said.

Nine states have simply declared that there is a zero tolerance for marijuana use and driving, meaning that any amount in one's blood could be grounds for a DUI, but this gets complicated with people's medical marijuana use, and those who may be frequent users who maintain persistent levels of THC in their blood long after they were actually high.

As far as the traffic death count in Washington is concerned, it does appear to suggest some causality between legalization, more people getting high, and more people driving while impaired, and the National Cannabis Industry Association is thus unhappy about it. As CNN notes, they point to a different study by the Transportation Department that asserted that driving while drunk held a much greater risk of getting into an accident than driving while stoned.

Still, AAA now recommends a dual approach, with law enforcement testing both for blood levels of THC and administering a behavioral and psychological exam to determine impairment.

Previously: CA Lawmaker Proposes Statewide Use Of Roadside Marijuana And Opiate Test