DUI charges may have to be thrown out in hundreds of DUIs after DUI defense lawyers in San Francisco have caught out a problem with the proper calibration of the Alco-Sensor IV machine (same machine used in LA County) used to test breath at the scene. The problem goes back for years.
The San Francisco police has not been properly testing the accuracy of the Alco-Sensor IV machines. Instead, the cops were just filling out the paperwork. The machine needs to be tested every 10 days or 150 actual tests by hooking a cylinder of gas up to the Alco-Sensor IV and running a test. This tells whether the particular machine is testing accurately because the amount of alcohol by volume in the cylinder is known. The cops laziness was discovered when DUI defense attorneys noticed that every test performed on the machines was exactly accurate. For this to happen is a mathematical impossibility.
The Alco-Sensor IV is used to test a subject's breath at the scene. It is used by officers to determine probable cause. It is not a sufficiently accurate test to provide the proof necessary to sustain DUI charges at trial. The cases where it has been used are subject to dismissal because without probable cause the cops cannot arrest the person accused.
The CHP separately did an audit of the SFPD's use of the machine and found that the cops were not in compliance because they were not testing the machine for accuracy prior to using it.
If you have questions about your breath test, or any other DUI related issue please call me at (213) 479-5322.