Police conducting sobriety checkpoints must follow strict criteria laid out by the California Supreme Court in the landmark case Ingersoll vs. Palmer. If police do not follow the protocol described in Ingersoll, the checkpoint is not lawful, and any evidence gathered during a drunk driving arrest may not be admissible in court. A California attorney who specializes in defending DUI / DWI cases can determine whether a sobriety checkpoint was conducted lawfully.
The Supreme Court identified eight factors that minimize the intrusiveness on the individual, while balancing the needs of society to keep drunk drivers off the road.
According to the Ingersoll decision, the establishment and location of sobriety checkpoints must be decided by supervisory police officers, not officers in the field. This requirement is important to reduce the potential for arbitrary and random enforcement.
The Supreme Court’s ruling also placed limits on the discretion of police to stop drivers at checkpoints. Police must use a neutral mathematical formula, such as every driver, or every third, fifth, or tenth driver to determine who to stop. This requirement takes away the discretion of the individual officer to choose to stop individual drivers without any legitimate basis.
Police also must give primary consideration to maintaining safety for motorists and officers. In order to minimize the risk of danger to motorists and police, proper lighting, warning signs and signals, and clearly identifiable official vehicles and personnel are required. The checkpoint should only be operated when the traffic volume allows the operation to be conducted safely.
The locations of roadblocks also are regulated. A supervisory officer must choose a location that will be most effective in actually stopping drunk drivers, such as roads which have a high incidence of alcohol-related accidents and arrests.
The time and duration of sobriety checkpoints also are of key importance. Police are expected to exercise good judgment in setting times and durations, with an eye to effectiveness of the operation, and with the safety of motorists in mind. As long as these considerations are in effect, there are no hard and fast rules as to the timing or duration of the roadblock.
Sobriety checkpoints also must be established with high visibility so that drivers can easily see the nature of the roadblock. The features that promote high visibility include flashing warning lights, adequate lighting, police vehicles, and the presence of uniformed officers. Not only are such factors important for safety reasons, but advance warning will reassure motorists that the stop is duly authorized.
Police operating sobriety roadblocks should detain each motorist only long enough for the officer to question the driver briefly and to look for signs of intoxication, such as alcohol on the breath, slurred speech, and glassy or bloodshot eyes. If the driver does not display signs of impairment, he or she should be permitted to drive on without further delay. If the officer does observe signs of impairment, the driver may be directed to a separate area for a field sobriety test. At that point, further investigation must be based on probable cause, and general principles of detention and arrest would apply.
Police conducting a lawful sobriety checkpoint must provide advance notice of the roadblock to the public, although they are not required to disclose its specific location. Publicity both reduces the intrusiveness of the stop and increases the deterrent effect of the roadblock. The thought is that advance notice limits intrusion upon the individual’s personal dignity and security because those stopped would anticipate and understand what was happening. Further, advance publicity serves to establish the legitimacy of roadblocks in the minds of motorists.
The Supreme Court also stated that motorists who seek to avoid a roadblock may not be stopped and detained merely because they attempted to avoid the roadblock. However, if the motorist commits a vehicle code violation or displays obvious signs of intoxication, there is adequate probable cause to pull over the motorist, after which point general principles of detention and arrest apply.
Although the Supreme Court’s Ingersoll decision legitimized sobriety checkpoints, it also established strict guidelines under which the roadblocks must be operated. If law enforcement does not follow the factors set out by the Supreme Court, the evidence gained as a result of the roadblock may be suppressed as a violation of the Fourth Amendment rights of the motorist. A DUI / DWI lawyer who is well-versed in the requirements of sobriety checkpoints can determine whether a roadblock was lawfully executed, and whether any evidence gathered is likely to be suppressed.