Retrograde Extrapolation
Retrograde extrapolation is an attempt by the state to prove that a person's blood alcohol concentration (BAC) was higher when the police initially made the traffic stop and DWI / DUI arrest. Occasionally, the police initiate a traffic stop and make an arrest for DWI / DUI under the presumption that the person's BAC is above .08. Once the person provides a breath or blood sample, the results are below the statutory limit of .08. If the state is unable to prove that the amount of alcohol that the person consumed negatively effected their ability to operate a motor vehicle, they may attempt to prove BAC at the time of arrest by retrograde extrapolation.
Retrograde extrapolation is a scientifically flawed procedure that results in nothing more than an educated guess. To put it simply, it is nothing more than voodoo science. To prove previous BAC, the state attempts to extrapolate the BAC results back to an earlier time when they were supposedly higher. The state attempts to provide a scientific formula, which considers the amount of time that transpired from the initial police contact to the evidentiary BAC test.
The formula, for example, may presume that the average individual eliminates alcohol from their body at a rate of .015 per hour. This is dependent on a number of factors, primarily body weight, but a good rough estimate of how fast alcohol is eliminated from your body. Thus, if a person was a .09 roadside, during the time of arrest, and it took the police an hour to transport and conduct an evidentiary BAC test, that person may only blow a .07 for record. In North Carolina, alcohol test results are truncated to two decimals. So that person may actually be a .075, but North Carolina results will only show a .07. Truncation is a good thing for those charged with DWI.
The concept of retrograde extrapolation is flawed because it boils down to nothing more than a guess. Each person handles alcohol differently. BAC test results vary widely based on weight, age, sex, drinking experience, prior food consumption, time of consumption, etc. There are a number of factors that come into play. Retrograde extrapolation does not reflect a fair and accurate representation of a person's actual BAC during the time of arrest. It is virtually impossible to meet the criminal standard to convict of beyond a reasonable doubt using such an unreliable method. Although retrograde extrapolation is rarely used and typically reserved for more serious DWI cases, it is a tool that the state has, and it is important to be aware of it and prepare accordingly.
Contact Adkins Law if you need to speak to a DWI lawyer / DUI lawyer. A DWI lawyer from Adkins Law will be happy to give you a free DWI consultation. Adkins Law offers DWI representation in Huntersville, Cornelius, Davidson, Charlotte, Mecklenburg County, Iredell County, Gaston County, Cabarrus County, and the Lake Norman area.
Retrograde extrapolation is an attempt by the state to prove that a person's blood alcohol concentration (BAC) was higher when the police initially made the traffic stop and DWI / DUI arrest. Occasionally, the police initiate a traffic stop and make an arrest for DWI / DUI under the presumption that the person's BAC is above .08. Once the person provides a breath or blood sample, the results are below the statutory limit of .08. If the state is unable to prove that the amount of alcohol that the person consumed negatively effected their ability to operate a motor vehicle, they may attempt to prove BAC at the time of arrest by retrograde extrapolation.
Retrograde extrapolation is a scientifically flawed procedure that results in nothing more than an educated guess. To put it simply, it is nothing more than voodoo science. To prove previous BAC, the state attempts to extrapolate the BAC results back to an earlier time when they were supposedly higher. The state attempts to provide a scientific formula, which considers the amount of time that transpired from the initial police contact to the evidentiary BAC test.
The formula, for example, may presume that the average individual eliminates alcohol from their body at a rate of .015 per hour. This is dependent on a number of factors, primarily body weight, but a good rough estimate of how fast alcohol is eliminated from your body. Thus, if a person was a .09 roadside, during the time of arrest, and it took the police an hour to transport and conduct an evidentiary BAC test, that person may only blow a .07 for record. In North Carolina, alcohol test results are truncated to two decimals. So that person may actually be a .075, but North Carolina results will only show a .07. Truncation is a good thing for those charged with DWI.
The concept of retrograde extrapolation is flawed because it boils down to nothing more than a guess. Each person handles alcohol differently. BAC test results vary widely based on weight, age, sex, drinking experience, prior food consumption, time of consumption, etc. There are a number of factors that come into play. Retrograde extrapolation does not reflect a fair and accurate representation of a person's actual BAC during the time of arrest. It is virtually impossible to meet the criminal standard to convict of beyond a reasonable doubt using such an unreliable method. Although retrograde extrapolation is rarely used and typically reserved for more serious DWI cases, it is a tool that the state has, and it is important to be aware of it and prepare accordingly.
Contact Adkins Law if you need to speak to a DWI lawyer / DUI lawyer. A DWI lawyer from Adkins Law will be happy to give you a free DWI consultation. Adkins Law offers DWI representation in Huntersville, Cornelius, Davidson, Charlotte, Mecklenburg County, Iredell County, Gaston County, Cabarrus County, and the Lake Norman area.