Santa Clara County prosecutors are taking a fresh look at hundreds of driving-under-the-influence cases in Palo Alto and San Jose after they learned Tuesday that the police departments in those two cities were using faulty alcohol-prescreening devices.
Both departments have been relying since last year on the Alco-Sensor V, an alcohol-prescreening device that prosecutors say sometimes malfunctions. Police use the device to measure a driver's blood-alcohol content.
The District Attorney's Office said the device has been used by the San Jose Police Department since November 2010. The Palo Alto Police Department has been using it since April 2010.
Prosecutors are now in the process of identifying 865 cases in which officers used the Alco-Sensor V devices to determine that a driver was intoxicated. They expect this process to take at least a month.
Once these cases are identified, the office will reach out to the relevant defense attorneys and unrepresented defendants, the District Attorney's office said in a statement. These devices, the statement noted, are "not in widespread use throughout Santa Clara County, nor were they the primary device used to determine a suspect's blood alcohol content."
Deputy District Attorney Rob Baker said the device is one of many tools officers have for determining a driver's level of intoxication. It is typically used after the driver has taken other tests, including walking in a straight line and counting numbers. The most important test is the chemical test the suspect takes at the police station after the arrest, he said.
Baker said the county's review includes 133 cases in Palo Alto, which stopped using the devices last December.
"It's only one factor in determining if the person is under the influence," Baker said, referring to the faulty devices. "I don't think it will result in a huge number of reversals or a lot of cases coming back to court."