A New Saliva-Based Marijuana Test Gives Condemning Results in Just 3 Minutes

Currently, there is no efficient way for police to scientifically test whether a driver is under the influence of marijuana. A new saliva-based weed test developed at Stanford University might soon change that.

The Shan Xiang Wang laboratory at Stanford has developed a new test that uses a magneto-nanosensor to track hints of marijuana in saliva in just three minutes, Digital Trends reports. At the moment, it is difficult for law enforcement to confidently tell whether weed has impaired a motorist because it generally requires a blood or urine test, which isn't viable by the roadside.

This new test uses a sensor that connects to a smartphone via Bluetooth and analyzes the sample at the scene. Instead of a state trooper having to look to unreliable signs of impairment—odor, red-rimmed eyes, or disorientation—he would be able to confirm chemically whether the driver breaking the law. A chemical test would also help lessen the impact of bias during stops.

“Most law enforcement officers are not authorized to take blood samples, while taking a urine sample on spot is extremely inconvenient." Professor Wang said to Digital Trends. "Detection of marijuana from saliva would bypass the trappings with either blood or urine samples.”

With the ongoing push for marijuana legalization, law enforcement is searching for ways to keep roads safe from "smacked" drivers.