Phoenix DUI Lawyer Blog

One Phoenix DUI Defense that Police Don't Want You to Know about...
"Retrograde Extrapolation"

Retrograde Extrapolation refers to the calculation of blood alcohol content (BAC) by estimating backwards from a later chemical test, in an attempt to determine what your
BAC level was at the time you were driving. Good Phoenix DUI Attorneys sometimes use this as a defense to present to the prosecution that you were not driving illegally, or impaired due to chemicals or alcohol at the time you were driving. Due to the existence of many variables, uncertainties, the complicated mathematical calculations, individual body absorption rates, and toxicology issues surrounding Retrograde Extrapolation, some states prohibit the DUI defense, or prosecution from using it.

The State of Arizona allows for admission Retrograde Extrapolation evidence, but only on a limited basis, meaning they must meet certain time restriction or other criteria in order to use it. Some of the best Phoenix DUI lawyers will still try use it in an appropriate case do defend you and challenge a DUI or Drug tests accuracy in order to suppress evidence or get your case dismissed. An argument can be made by your attorney that an unreasonable amount of time passed between when you were stopped for a Phoenix DUI and when you were tested for DUI or drugs. Therefore, causing the test to be inaccurate or invalid and not an accurate indicator of your impairment at the time you were driving.

A few factors that can result in delays from the time of the Phoenix DUI stop, and the time they were tested. Some common causes of delays include but are not limited to the following:

• You were suspected for Drug DUI, and it took an unreasonable amount of time to transport you to a facility, location, or arrange for qualified personnel to test you.

• A hit and run was involved, knowingly or unknowingly. You did or did not realize you hit someone at the time or you panicked and left the scene before the police arrived. Later, perhaps hours or day (s) you remembered or learned there was an injury involved; reported that you were the driver of the vehicle; and that you were driving under the influence of alcohol or drugs at the time.

• You had to be transported by ground or air ambulance to a hospital which took an unusually long time before you could be properly tested for qualified personnel.

• DUI involved a serious car accident which an unusual amount of time for the police to investigating the scene; a lengthy waiting or working around emergency crews; waiting for other police or traffic control officers to arrive before they had an opportunity to test you.

A good Phoenix Attorney may be able to get the evidence suppressed and case dismissed through the use of an expert, or by calculating the absorption level and elimination of alcohol from the body between the time you were driving and the time the tests were conducted. The rate of elimination in the average person is commonly estimated at .015 to .020 percent per hour. But this number is subject to fluctuations and many different factors for each individual. Generally the rate of your metabolism of drugs or alcohol can be effected by things such as bodyweight, body temperature, the type of drug or alcohol consumed, the amount, type and time of other food or fluids you may have consumed prior to the Phoenix DUI or Phoenix DUI with Drug stop by police.

Even though this defense has limits, it can still be a viable defense. An experienced Phoenix Arizona DUI Attorney may still challenge the breath or chemical testing to defend your case, and get your charges dismissed.

If you have been charged with any Phoenix DUI, Extreme DUI, Repeat Offense DUI, Under age 21 DUI, DUI with child under 15 in vehicle, Aggravated Felony DUI, Drug, Felony Drug, Dangerous Drug, Narcotics, Marijuana, any Phoenix DUI, Phoenix, Phoenix Drug DUI, or any other criminal charge including theft, assault, aggravated assault, domestic violence, drugs crimes, probation violations, robbery, computer crimes, ID theft crimes, or any other criminal charges contact the Law Office of James Novak, for your Free Consultation at (480) 413-1499. Speak directly with experienced Phoenix Criminal Defense and DUI Defense Attorney and James Novak (Former Prosecutor).