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How accurate are breath test devices?

| Nov 7, 2019 | DWI

In a recent post, we discussed some of the basic elements of a drunk driving stop in Pennsylvania. One aspect of a DUI stop is the breath test. Typically, police ask drivers to take breath tests twice: once during a stop and later at the police station, if they arrest the driver.

Considering how standard these tests are and how frequently law enforcement agencies use them as evidence of intoxication, it makes sense to assume they are practically perfect. However, according to a recent report from the New York Times, this is not the case.

Problems with precision

Breath test devices are often promoted as having the capability to precisely calculate the amount of alcohol in a person’s system. In reality, though, courts across the country have determined that tens of thousands of devices and test results are faulty.

There have been cases where miscalibration skews results or police departments disable features designed to improve calculations. Some devices are built improperly; chemicals used by the machines can expire and lose potency; programmers can make mistakes in the software.

In other words, there is plenty of room for error when it comes to the accuracy of breath test machines.

Without precise calculations and reliable testing methods, breath test devices are hardly a perfect measure of a driver’s blood alcohol concentration. Therefore, it can be wise to scrutinize them in a DUI case where the results do not align with the facts.

Challenging results, dismissing charges

Parties who can successfully challenge elements of a DUI arrest may see their charges reduced or completely dropped. This is especially important to understand if a breath test is the primary evidence against a driver. Casting doubt on the results, device or operation could make these tests inadmissible, leaving prosecutors with little or no evidence to support DUI charges.

However, this can be complicated, so legal counsel can be crucial when defending against a DUI. Contact an attorney at the Quinn Law Firm for a free consultation by calling us at 814-806-2518.