In some Rochester DWI cases, a lawyer may use the term “extrapolation” when discussing the breath test result.

The word extrapolation generally refers to the ability to estimate a value beyond the range of what was measured based on what has been measured.

In terms of the breath test, it refers to the ability estimate the defendant’s blood alcohol content when he or she was driving based on a breath test score obtained up to two hours after he or she stopped driving.

New York’s DWI laws forbid driving with a blood alcohol content of .08% or more (or .18%, for the offense of Aggravated Driving While Intoxicated).

In any case relying on a breath test score, the prosecution must prove beyond a reasonable doubt that the defendant’s breath test score was above the legal limit at the time he or she was driving.

Obviously, it is not possible to test the driver’s breath when he or she is actually driving.

As a result, the prosecution often must rely upon a breath test administered well after the driver was stopped.

While a result over the legal limit on this later breath test is considered strong evidence that the driver’s blood alcohol content was above the legal limit when driving, it is not absolute proof.

This can be important in cases where the defendant’s breath test result is barely above the legal limit.

In such cases, the defendant has a strong argument that because a later test cannot precisely measure his or her blood alcohol content at the time of driving, the prosecution cannot establish beyond a reasonable doubt that the blood alcohol level was not actually lower at the time of operation.

The result of the breath test taken by the defendant will be a critical piece of evidence in any DWI case.

If you have been arrested, it is important to have an experienced DWI lawyer who understands the laws surrounding the breath test and the limitations of the test.

If you need legal help, call us at 585-484-7432.