Usually the most powerful evidence that the prosecutor has in a DUI case is the breathalyzer result. This is rarely the only piece of evidence in a DUI case, but prosecutors rely heavily upon breathalyzer BAC (blood alcohol content) in the vast majority of cases. For this reason, the Virginia legislature has implemented Virginia Code Section 18.2-268.2, the Implied Consent Statute.
Essentially this statute provides that any person who operates a motor vehicle on a "highway" in the Commonwealth consents through such operation to have samples of their blood, breath, or both taken for a chemical analysis to determine the alcohol content in the blood. Unreasonable refusal to submit to a breath or blood test will result in a charge under 18.2-268.3 for refusal to take a breathalyzer.
There are myriad ways to attack the implied consent statute for those charged with unreasonable refusal, and there are a myriad of ways to use the implied consent statute to suppress a blood or breath result in a DUI case. One of the most glaring deficiencies in the implied consent statute is that it only applies on "highways". This does not mean that it is limited to interstates, or even to major streets; however, it does not include private property, and it does not include parking lots. A motorist who is stopped for DUI in a parking lot can be convicted of DUI, but operating a motor vehicle in a parking lot does not invoke the implied consent statute, because a parking lot is not a highway.
The implied consent statute also only applies if the defendant is arrested within 3 hours of the operation of the vehicle. Further, the implied consent statute applies only after a lawful arrest. Every DUI charge involving a breathalyzer result must be examined closely to find the possible defects in police conduct that can result in suppression of the result.
In Virginia, unreasonable refusal to submit to a breathalyzer results in a 1 year suspension of drivers license, pursuant to 18.2-268.3. The code specifically prohibits issuance of a restricted drivers license during this one year period. The result is that an individual convicted of unreasonable refusal cannot operate a motor vehicle anywhere for the next year. This is a serious sanction, and in many ways is worse than the penalties for the DUI itself!