Field Sobriety Test Defense Lawyer in San Jose, CA Clue Counts, Criteria and Accuracy

Three tests, and what the manual claims for each

The National Highway Traffic Safety Administration's standardized field sobriety test battery consists of horizontal gaze nystagmus, the walk and turn, and the one leg stand. The agency's refresher participant manual states that an officer should look for three clues of nystagmus in each eye, lack of smooth pursuit, distinct and sustained nystagmus at maximum deviation held for a minimum of four seconds, and onset of nystagmus prior to 45 degrees, for a maximum of six clues across both eyes. The stated decision criterion is four: if a person exhibits at least 4 out of the possible 6 clues, the implication is a BAC above 0.08, and the manual puts the accuracy of that criterion at 88 percent (NHTSA SFST Refresher Participant Manual).

The walk and turn has eight clues and a criterion of two

The same manual lists eight distinct clues for the walk and turn: cannot keep balance while listening to the instructions, starts too soon, stops while walking, does not touch heel to toe, steps off the line, uses arms to balance, improper turn, and incorrect number of steps. The stated criterion is that if a subject exhibits two or more clues or cannot complete the test, the officer classifies the blood alcohol concentration as at or above 0.08, with an accuracy figure of 79 percent. The one leg stand has a maximum of four clues, sways while balancing, uses arms to balance, hopping and puts foot down, with the same two-clue criterion and a stated accuracy of 83 percent (NHTSA SFST Refresher Participant Manual). Two figures follow from those numbers. The tests are scored, not measured, and the manual's own accuracy claims are not 100 percent.

The screening device is a field sobriety test by statute

California law places the handheld breath device in the same category. Vehicle Code section 23612(h) states that a preliminary alcohol screening test is a field sobriety test and may be used by an officer as a further investigative tool, and subdivision (i) requires the officer to advise the person that the test is being requested to assist in determining whether that person should be arrested, that the test does not satisfy the obligation to submit to a chemical test as required by the section, and that the person may refuse to take the screening test (Vehicle Code 23612).

If a screening result is used as a number, the regulations apply

A screening device produces a breath figure, and Title 17 does not exempt it from the rules that govern breath analysis. Section 1221.1 provides that the breath sample shall be collected only after fifteen continuous minutes during which the subject must not have ingested alcoholic beverages or other fluids, regurgitated, vomited, eaten or smoked (17 CCR 1221.1). Section 1221.2 requires that breath alcohol testing include analysis of two separate breath samples whose results do not differ from each other by more than 0.02 grams per 210 liters of breath, requires accuracy checks against reference samples within plus or minus 0.010 grams percent of the true value, and defines periodic for that purpose as either a period of time not exceeding 10 days or following the testing of every 150 subjects, whichever comes sooner (17 CCR 1221.2).

What the observation record has to contain

Because the tests are scored from observation, the report is the evidence. The clue counts published in the manual are specific enough to be checked against a narrative: which clues were recorded on each eye, whether maximum deviation was held the stated four seconds, whether the instructions were given in the standardized sequence, whether the walking surface and lighting allowed the exercise, and whether a physical condition, footwear or an unlevel shoulder was noted. The same is true of the sequence of advisements. Section 23612 requires specific things to be said and, where a breath test is followed by a blood request on a drug theory, requires the officer to state in the report the facts on which that belief and request are based.

The San Jose record, and the two proceedings that use it

The officer's observations end up in two files. Section 13380 requires the officer to submit a sworn report to the department, and section 13557 requires the department to determine by the preponderance of the evidence whether the officer had reasonable cause to believe the person was driving in violation of section 23136, 23140, 23152 or 23153, whether the person was lawfully arrested, and whether the stated blood alcohol threshold was met (Vehicle Code 13557). That review happens at the Driver Safety Office serving this area, at 90 Great Oaks Blvd., Suite 104, in San Jose (California DMV). The criminal file goes to the Hall of Justice at 190 West Hedding Street for a San Jose arrest (Santa Clara County Superior Court). Section 13558 states that at the administrative hearing the evidence is not limited to what was considered at the review, which is why the roadside record is examined twice on different rules. This page is general information about California law and is not legal advice. A person whose case rests on roadside testing should speak with a licensed California attorney, and the attorney advertising here can be reached at the posted number.