Scientists develop weed breathalyzer — will it actually work?

Now that 33 states and Washington, D.C., have legalized marijuana for some purposes, there are many people who use the drug who then wish to drive. Even in weed-friendly states however, it is illegal to drive while high.

Here in Tennessee, you can be convicted of DUI if you have any detectible amount of THC, marijuana’s psychoactive compound, in your blood.

There are some important legal and practical issues around driving while high in states where cannabis is legal. For one, it makes no sense to have an “any detectible amount” standard, because people are able to legally use cannabis and THC is detectible for approximately a month after use — long after the “high” phase has passed. Therefore, police officers need to be trained on how to recognize drivers who are actually high, versus those who smoked a legal joint three weeks ago.

Law enforcement would very much like to have a “weed breathalyzer” that could tell the difference between someone who is intoxicated and someone who is past the intoxication stage. That has been a scientific challenge, however, as there is no established amount of THC that correlates with intoxication.

In the past, some scientists and engineers have been able to build preliminary weed breathalyzers, but none has come as close to becoming commercially available as one just completed by a team from the University of Pittsburgh.

Machine can detect THC, but there is still nothing to correlate with

A chemistry professor and an electrical and computer engineering professor at the University of Pittsburgh made a breakthrough in their weed breathalyzer project. Instead of trying to miniaturize a mass spectrometer, the machine currently used to detect THC in blood, the team produced a device that relies on nanotechnology.

When breath is drawn across the device, it encounters tiny carbon nanotubes. If there is THC present, it binds with the nanotubes, changing their electrical properties.

The team says that it could be ready to mass-produce the machine in a few months if they had a suitable industrial partner.

There’s still the problem, however, of determining whether someone is actually high or simply has leftover THC in their system from an earlier, legal use. The new device may be able to put a number on how much THC is present in a sample, but that doesn’t mean much until we know how much THC makes a person high.

Arrested for DUI-drugs after using weed legally?

Have you traveled to a weed-friendly state, consumed weed legally and been charged with DUI here in Tennessee? You should contact a defense attorney right away. The fact that you used weed completely legally could have an impact on your DUI case.

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