Almost every DUI case in Virginia involves a breath or blood test. This evidence is often the most important evidence the police has against a person in a DUI case. This evidence, however, can in some cases be incorrect.

In every DUI case it is very important to review all the evidence against you including a blood or breath test.

Drivers in Virginia can be pulled over when there is reasonable suspicion that the driver is under the influence of alcohol or where the officer believes the driver has committed a traffic infraction or other violation of law.

Typically the officer will then conduct field sobriety tests to determine whether or not the driver is under the influence of alcohol. If the Officer believes that the driver is under the influence of alcohol the officer will then arrest the driver, and the driver will then be subject to a breath or blood test to determine his or her BAC level.

Factors that influence your BAC level?

In Virginia, drivers operating a motor vehicle on a highway are subject to implied consent. This requirement allows the police to test your BAC. 

However, even where the results of the breath test indicate that you were over the legal limit you're not automatically guilty of a DUI. There can be inaccuracies in the blood or breath test that you are required to take once arrested. A breathalyzer result that is either invalid or inaccurate may be drivers best defense in a DUI case.

There are a whole host of reasons why a test result may be either invalid or inaccurate. The factors that can affect the test include:

• Certain medical conditions
• The amount of time that has passed since you consumed alcohol
• The presence of mouth alcohol
• Exposure to substances that effects of alcohol
• Your body temperature
• The officer's failure to observe required procedures under Virginia code.

Please see below for more information relating to breath tests pursuant to DUI cases in Virginia.

1. May a driver refuse to complete a breath test in Virginia?

There are typically two breath tests involved in a DUI investigation.

1. The first breath test that is typically conducted is a PBT test (preliminary breath test). This is the test used by the police on the side of the road prior to an arrest. This test is generally not admissible in court, but there are exceptions, such as where the driver is challenging sufficient probable cause for the arrest.
2. There is also the official breath test which is completed at the magistrates office or at the jail. This test is completed after the defendant has already been arrested. This is what the prosecutor will try to introduce into evidence to show that you were in violation of the DUI law.

1.1 Preliminary Breath Tests

Many police officers in Virginia carried PBT's with them while on patrol. These tests are used to help the police officer determine whether or not the driver is intoxicated, and can be used to support probable cause for the arrest, if probable cause is challenged in a suppression hearing at trial or prior to trial.

The officer is required to offer the PBT to a driver in the course of the DUI investigation; however, failure to offer the PBT does not result in the dismissal of charges against the driver. The driver is not required to submit the PBT test and failure to take this test is not evidence of consciousness of guilt.

PBT devices are subject to requirements pursuant to the Virginia code and the Virginia administrative code. It is important when investigating a DUI case to determine whether or not the device was in compliance with the legal requirements under Virginia law.

1.2 Official breath test made subsequent to DUI arrest

Presuming the officer has arrested the driver for DUI, and the requirements of implied consent have been met, the driver is required to submit to a breath (or blood) test. Generally, the driver is required to submit to the breath test and does not have the choice of having a blood test performed rather than the breath test; however, there are times when a blood test is appropriate rather than the breath test.

If the driver does refuse to submit to the required tests the driver will be subject to a civil penalty for refusal which carries a mandatory one-year license suspension and the driver is not eligible for a restricted driver's license in Virginia.

1.3 Legal requirements relating to breath test procedures

Virginia code section 18.2 – 268.9 that support the requirements relating to the validity of breath test results. There are numerous requirements under this code section.

In order for a breath result to be admissible in court the individual conducting the tests must possess a valid license to conduct such a test. Furthermore, the equipment itself and the methods used must also be approved by the Department of Forensic Science.

The breath test operator who conducts the test must issue a certificate which must indicate in test was conducted in accordance with department standards.

Substantial compliance with the statute is all that is required under Virginia law.