DUI Traffic Stops

DUI Traffic Stops San Francisco DUI Attorney Discusses DUI Traffic Stops

Driving under the influence of alcohol or drugs is against the law in California, and being charged with such an infraction is a good reason to consult a San Francisco DUI attorney. There are certain parameters a police officer must follow when a driver is stopped, and failure to do so could nullify the charges. Having an appropriate drunk driving defense is important in order to protect a driver’s rights.

Are There Rules for Stopping a Driver?

Rules for stopping a vehicle involve the concept of probable cause. A police officer needs a reason to pull a driver over. In the case of drunk driving, the officer might observe erratic driving or swerving across an intersection. In addition, disobeying other traffic rules would be cause to stop you. In such cases, your San Francisco DUI attorney may review the police report to determine if the traffic stop was based on probable cause.

Other Factors That Might Be Considered

If a driver is involved in an accident, a police officer would have probable cause to investigate if alcohol is suspected. In addition, other factors might be a driver who smells of alcohol, has bloodshot eyes, is clumsy when handing over paperwork, has slurred speech or is belligerent to the officer. Speaking to a San Francisco DUI attorney may be useful if this occurs.

What Happens If a Police Officer Believes the Driver Is Intoxicated?

If a police officer has reason to believe the driver is driving impaired, he or she may ask the driver to complete sobriety tests. There are different types of tests that can be done, including field sobriety and toxicology tests.

What Are the Types of Field Sobriety Tests?

The National Highway Traffic Safety Administration has developed three standardized tests to determine if an individual is impaired. The first, Horizontal Gaze Nystagmus, measures the degree of nystagmus that occurs when the eyes are rotated. Some degree of involuntary rapid eye movement occurs normally when the eyes are rotated upward. However, in someone who is impaired, exaggerated nystagmus will occur at a lower degree of rotation. The officer who administers the test interprets the results. If administered properly, there is a high degree of correlation with drunk driving in about 88 percent of cases. Two other field sobriety tests include the walk and turn and one that asks the driver to stand on one leg. The walk and turn involves walking a certain number of steps in a heel-toe format, then turning and walking back. Standing on one leg and counting is the other field sobriety test administered. Correlation with impairments is 79 and 83 percent respectively. Both tests are done to see if the driver can maintain balance and follow instructions. If this is not possible, the officer may conclude the driver is impaired.

Toxicology Tests

If there is reason to suspect that a driver is inebriated, he or she may be asked to undergo screening tests at the roadside. The tests look for the alcohol content in the driver’s blood either directly or by using mathematical calculations. A DUI attorney might provide additional information concerning such tests. Generally, a blood alcohol level of 0.08 percent is the legal limit for alcohol intoxication. In drivers under 21 years of age, a lower limit is used. In addition, a lower threshold is used for truck drivers.

Submitting to Toxicology Tests

In most states, when you apply for a driver’s license you agree to submit to toxicology testing if appropriate circumstances exist. It is possible to refuse, but doing this may result in a license suspension and other sanctions. Usually, a screening breath test is done; however, you might be asked to choose between a urine, blood or breath test. Certain medical conditions might affect the use of a blood test. The police officer is required to inform you of what might happen if you refuse.

The DUI Defense

A DUI defense, as structured by a San Francisco DUI attorney, will look at each step in the process to see if proper protocol has been followed. Looking at test results and determining if there were flaws in testing or lack of probable cause are important aspects. For instance, if there was no reason to suspect you were impaired while driving or if you did not disobey a traffic law such as speeding, you may ask the court to allow a motion to suppress by which the entire case may be dropped. Performing a search for drugs might require a warrant but not always. If you do not consent to a search unless a warrant is in hand, you might be able to suppress the results from evidence.

Talking to an Attorney About Test Flaws

The field sobriety tests make assumptions on dexterity. Not everyone, either due to age or infirmity, is able to stand on one leg or walk heel to toe. The Horizontal Gaze Nystagmus is difficult to evaluate without the officer being appropriately trained. Field sobriety tests require certain standards be used in administering them. Deviation may allow a San Francisco DUI attorney to challenge the tests at trial.

Disputing Toxicology Tests

Tests used to determine the blood alcohol level also require that parameters be met. For instance, a Breathalyzer machine requires careful calibration. If the machine was not calibrated, the results may be questioned. Blood samples must be taken and handled in a specific manner. If the techniques used are faulty, your attorney may use this to challenge the charge of DUI. If you refused a toxicology test, this might be negatively construed at trial.

Contact a San Francisco DUI Attorney

A DUI charge may be challenged if appropriate steps are not taken or if information is not documented correctly. Contact a San Francisco DUI attorney from Silveira Law at (415) 795-3890, who can review your case and help you address the charges.