If an officer administers a breathalyzer test that comes back negative — but they still suspect the driver is intoxicated – there are no scientifically backed options available to test for drug-related impairment during the traffic stop.

But there are controversial options, including roadside drug tests and a 12-step process that officers trained as "Drug Recognition Experts" (DRE) use to justify arrests.

Katelyn Ebner of Georgia learned about the latter option and exposed its shortcomings after she was wrongly arrested and jailed on suspicion of driving under the influence of marijuana last year, HuffPost reported.

Cobb County Police Officer Tracy Carroll was convinced that the 23-year-old was high, and as a certified DRE, he decided to put the driver through a series of tests to prove it. The 12-step process DREs are trained to follow include interviews, checking vital signs, eye examinations, physical inspections, and finally a drug test.

"You’re showing me indicators that you have smoked marijuana," Carroll told Ebner, according to dash cam footage.

She was jailed overnight, and the charge caused her to lose her alcohol server's permit, which she needed to work. It was only four months later, when the drug tests results came back negative that she proved her innocence.

Criminal defense attorneys have argued that the "Drug Influence Evaluation" (DIE) that these certified officers follow are flawed. DREs are "cops in lab coats masquerading as scientist," Fresno defense attorney Eric Schweitzer told The Sacramento Bee, and the training program amounts to "pseudoscience."

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The suggestion that officers can not only identify drug-related intoxication but pinpoint what drug is being used through observational tests is unscientific, Schweitzer said.

While there are detectable signs of drug use, such an as elevated or depressed pulse and dilated pupils, these can also be explained by numerous factors — fatigue, allergies, and nervousness, for example — that are unrelated to substance use. Law enforcement officials have recognized the shortcomings of the DRE program, but they insist that the certification process is in the vital interest of public safety. Without a drug-equivalent breathalyzer, DRE training is the next best means of deterring impaired driving, according to the International Association of Chiefs of Police (IACP).

But the research that law enforcement agencies have used to support these specialized field tests has been debunked. A 2013 peer-reviewed study published in the Journal of Negative Results in Biomedicine reviewed earlier research used to validate DRE arrests. Those studies concluded that DREs accurately identified drug-related impairment in 84 to 98 percent of cases.

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Dr. Gerg Kane, an expert witness in DUI cases who reviewed these findings, concluded that they "do not validate current DIE practice."

The studies supporting these field tests didn't "reference testing of driving performance or physical or mental impairment," focused on tests that are "different from those currently employed by U.S. law enforcement," and "used methodologies that biased accuracies," the study found.

There were about 5,700 DREs throughout the U.S. in 2012, according to a 2012 annual report from the IACP, and the organization's goal is to expand the program in response to marijuana legalization efforts. Accuracy aside, it's unclear whether these programs have effectively deterred impaired driving — but it's certain that, with more DREs on the road, there will continue to be wrongful arrests like Ebner's.