California DUI checkpoints must follow strict criteria set forth by the California Supreme Court in Ingersoll vs. Palmer. If the police do not follow these constitutional requirements outlined in Ingersoll, the checkpoint is not lawful. That means any evidence gathered during a San Diego California DUI arrest may not be admissible in San Diego Superior Court nor relied upon to suspend one's driver's license at a California DMV administrative per se hearing.

The California Supreme Court pointed out 8 factors that minimize the intrusiveness on the individual, while balancing the needs of society to keep drunk drivers off the road.

First, the establishment and location of San Diego California DUI 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. drivers at San Diego California DUI checkpoints.

San Diego California DUI 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.

San Diego California DUI 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 San Diego California Drunk Driving checkpoint should only be operated when the traffic volume allows the operation to be conducted safely.

The locations of San Diego California DUI roadblocks also are regulated. A supervisory officer must choose a location that will be most effective in actually stopping San Diego California drunk drivers, such as roads which have a high incidence of alcohol-related accidents and San Diego California DUI arrests.

The time and duration of San Diego California DUI sobriety checkpoints 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 California Drunk Driving roadblock.

California Drunk Driving 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.

California Drunk Driving 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 California Drunk Driving field sobriety test. At that point, further California Drunk Driving investigation must be based on probable cause, and general principles of detention and arrest would apply.

California Drunk Driving 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 California Drunk Driving roadblocks in the minds of motorists.

The Supreme Court pronounced that motorists who seek to avoid a roadblock may not be stopped and detained merely because they attempted to avoid the California Drunk Driving roadblock. However, if the motorist commits a California vehicle code violation or displays obvious signs of intoxication, there may be adequate probable cause to pull over the motorist.

Although the Supreme Court's Ingersoll decision legitimized California Drunk Driving checkpoints, it established strict guidelines under which the roadblocks must be operated. If California DUI law enforcement do not follow the factors set out by the California 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 and may not be the basis to support a finding of a lawful arrest at a California DMV license suspension hearing.

A San Diego California DUI Defense Attorney can determine whether a San Diego DUI sobriety checkpoint was conducted lawfully.