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 a myriad of 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!

The situation is different for individuals stopped for DUI on federal property (such as any of the military installations in Hampton Roads).  Federal law provides for implied consent under 18 U.S.C. 3118, but it is not nearly as expansive (or as harsh), as the corresponding state code.  The difference arises because licensure of drivers is a state function; in other words, we do not get our drivers licenses from the federal government, so the federal government does not control whether or not Americans possess a drivers license.  Because of this, the only sanction for unreasonable refusal to provide a breath sample when arrested for DUI on federal property is loss of driving privileges on federal property for the next year (although the code also provides that the fact that the individual refused the breathalyzer may be admitted as evidence against them at trial for the DUI itself). 

The bottom line is that if you have been charged with DUI, either in state or federal court, you need to call our office for a free consultation.  Whether you took a breathalyzer or not, the implied consent statute can be used under the right circumstances as a tool against the government.  The consultation is free, so let's sit down and discuss your case.