Law enforcement in Massachusetts may have a new tool that detects THC levels in saliva as well as identifies drugs such as cocaine, heroin and morphine. Although the device, developed by researchers at Stanford University, still needs to be tested and approved by regulators, scientists say it can successfully detect molecules of THC using a simple roadside spit test. The same method can be used to detect molecules belonging to other drugs as well.

Police face two obstacles in enforcing laws against the use of marijuana while driving. One is that some states do not have a maximum permitted limit for THC. The other is that there is not a quick test that can quickly check for the presence of THC in the same way that a Breathalyzer can measure blood alcohol. Usually, a blood or urine test must be sent to a lab so that it can be checked for THC, which presents a problem for police making a traffic stop.

In addition to the saliva test being quicker and less invasive, researchers say that it is also more reliable in that THC in saliva correlates more to impairment than THC in blood or urine does. The test could also screen for multiple substances at once.

A person facing charges related to driving under the influence of alcohol or drugs might be facing severe penalties, including fines or jail time. The seriousness of the penalty may be related to a person’s prior convictions, and people with multiple convictions might want to focus on reducing the penalties. People charged for the first time may want to try to get the charges reduced or dropped. For example, if the person can demonstrate that a test was conducted improperly, that evidence might not be permissible in court. A plea bargain may also be an option.