I’m sure you’ve seen the billboards: “Report Drunk Drivers. Call 9-1-1.” The CHP and other agencies even have tips for spotting and reporting a drunk driver. So, let’s say you see a car weaving somewhat on the road and you suspect a drunk driver. You call 9-1-1 and report the driver, your location, and the license plate number of the weaving vehicle. What happens next?
Generally, the local law enforcement agency with jurisdiction over the location will respond. Perhaps they will observe the vehicle and determine that the driver is violating a traffic law (such as Vehicle Code section 21658, lane change violation) and effect a legal traffic stop. If the detaining officers end up finding probable causeto believe the driver is under the influence of alcohol or drugs, a legal arrest will be made.
But what if the officers locate the vehicle but it is not moving? Say the driver is parked with the engine off. Can the officers still confront the driver and potentially arrest him or her if there is reason to believe the driver is under the influence? After all, the driver is not driving, and the DUI law prohibits drivingunder the influence. Over 25 years ago, in the seminal case, Mercer v. Department of Motor Vehicles, the California Supreme Court held that “driving” under the DUI law requires evidence of observed volitional movement of the vehicle.