The U.S. Supreme Court decision, Missouri v. McNeely, is still having repercussions when it comes to laws concerning driving under the influence. That matter dealt with a warrantless blood test which allegedly indicated levels of blood alcohol among the driver of above the legal level. The Supreme Court ruled that blood draws could not be conducted if the individual arrested refused to consent without a warrant or "exigent circumstances."
Law enforcement officers expressed concern that alcohol might disappear from the bloodstream while delays were taking place to obtain a warrant. The Supreme Court, however, did not allow such a concern to be considered an "exigent circumstance" that would allow for a warrantless blood draw to take place.
Because of this ruling county prosecutors have decided in at least one case against brining in results of the blood test into evidence. A woman was accused of striking two individuals in a crosswalk. An arresting officer claimed to have smelled a strong odor of marijuana in the car and a warrantless blood sample was eventually taken from the driver without the driver's voluntary consent.
The woman was originally facing felony charges of vehicular homicide and reckless endangerment. Instead a plea deal was offered where the driver pled guilty to misdemeanor reckless endangerment and DUI. Prosecutors may have offered the plea deal in light of the Supreme Court decision because the driver could have challenged the warrantless blood test findings in court.
It must be kept in mind that delays will not in many cases make the DUI charges go away. Drivers charged will still require an attorney to defend them in DUI matters. The Supreme Court decision merely means that no state, whether it be Virginia or elsewhere, can order a warrantless blood draw of a driver without that driver's consent minus "exigent circumstances" acceptable to the court.
Source: ABA Journal, "SCOTUS ruling could complicate laws on impaired driving," Lorelei Laird, April 1, 2014