Drivers suspected of being under the influence of marijuana may soon be subjected to on-site chemical tests, similar to those used in alcohol related DUI cases. California lawmakers recently introduced Senate Bill 1462, which would allow law enforcement officers to administer oral swab tests to drivers suspected of being under the influence of marijuana (and other drugs).
In alcohol related DUI investigations, law enforcement officers routinely use on-site Preliminary Alcohol Screening (PAS) devices, or "breathalyzers," to determine the presence of alcohol in a driver's blood. If the PAS test shows the presence of alcohol, then the officer has probable cause to arrest. However, there are currently no similar devices being used by law enforcement officers for marijuana DUI investigations. In marijuana DUI cases, officers must rely on objective signs of marijuana intoxication (red/glazed eyes, confusion, smell, possession of marijuana, etc.) to form probable cause.
SB 1462 would give law enforcement an additional tool in marijuana DUI investigations. Just as with alcohol DUI investigations, officers may have the ability to quickly determine whether marijuana or other drugs are present in a driver's system. With the new devices, officers swab the inside of a driver's cheek, place the swab onto a tray, and then push the tray into an electronic device (as seen here). The electronic device analyzes the saliva and gives a fairly quick reading as to what drugs, if any, are present in the driver's system.
There are a few problems with these new devices. First, nobody knows how accurate these new devices are. Many of them have not been independently studied and reviewed for accuracy. Although the results from the oral swab tests are rarely being used in court (aside from in Kern County), the day will come when they are routinely used in court. Until the accuracy of these devices is reviewed and confirmed, admission of their results into court should be challenged.
The second problem is that these devices do not give an indication as to the level of marijuana in a driver's blood, only whether or not it is present. However, the mere presence of marijuana in a driver's blood is not indicative of intoxication. As such, the results of the on-site swab tests have zero evidentiary value, as they do not provide any evidence of intoxication.