Researchers at Washington State University told state senators Thursday they hope to have marijuana breathalyzers in the field sometime next year, according to the Tacoma News Tribune.

Police officers in two Washington towns told KIRO 7 that recognizing people driving high can often be a challenge and would welcome the tool.

The legal limit under Washington’s recreational marijuana law is 5 nanograms of THC per milliliter of blood.

However, DUI lawyer Jon Fox said there is a long way to go before marijuana breathalyzer field tests will be used in the legal system.

“It would probably be a number of years before any new technology to measure THC in the blood, by measuring breath, would even be granted a hearing in court,” Fox said.

Fox said it took decades for alcohol breathalyzers to be trusted.

A spokesman for the Washington State Patrol also said officers would not be using the new breathalyzers when they first become available.  He said there is concern results may not be considered valid.