Christoph Law Offices, DUI & Criminal Defense
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Christoph Law Offices, DUI & Criminal Defense
Christoph Law Offices, DUI & Criminal Defense


  • Top Lawyers - San Diego Magazine
  • Former Deputy San Diego City Attorney
  • Former USMC Captain
  • Located Directly Across From Vista Courthouse
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Attorneys William R. Christoph & Nicholas W. Christoph

New investigation questions reliability of alcohol breath tests

According to a recent New York Times investigation, alcohol breath test devices are often unreliable. Researchers with the investigation found these devices could provide results that were up to 40% higher. Inaccurate results can lead to false allegations of drunk driving. This piece will delve into the two key reasons alcohol breath test devices provide inaccurate results discussed in the investigation: issues at the manufacturer level and failures with implementation of the devices.

Issue #1: Manufacturers questions for software errors

Getting a third party, unaffiliated review of the software used in breathalyzer machines is difficult, as manufacturers generally refuse to sell the same devices sold to enforcement officers to the public. However, in 2007 the New Jersey Supreme Court required a leading portable alcohol breath testing device manufacturer to allow experts to analyze the machine. The experts found the machines contained “thousands of programming errors.”

In one example, a calculation error could result in rounding up the findings. In another, if the machine experienced a discrepancy during testing it was supposed to print out an error. Instead, a software malfunction resulted in the machine printing off a result.

Issue #2: Failures with implementation of the device

These machines are highly sensitive devices that require calibration. Calibration can take an average of an hour per device and generally the input of data to set the machine. In one case, calibration of machines was completed using incorrect data. In another, officials hired inexperienced help to speed up the calibration process – resulting in failures to calibrate correctly before sending the machines into the field.

The machines also often use a series of chemical solutions to test the breath sample. A failure to use the right solutions can provide an inaccurate result. In one case out of Washington D.C., the machines used by officers contained old solutions used solutions. The solutions were so old that they had lost their potency and provided inaccurate results.

In addition to these programming errors, many states have chosen to disable safeguards within the machines designed to better ensure an accurate result. This included shutting of a fuel-cell system used for quality-control checks and turning off a feature designed to measure the driver’s breath temperature. The machines should not be used if the breath temperate is over 93.2 degrees. Using at a higher temperature generally leads to inaccurately high results. Other attempts to fix devices that were producing inaccurate devices also resulted in scrutiny. One example: drilling a hole in the side of the machine to allow for better airflow.

Take home lesson: What are drivers to do if the state accuses them of drunk driving?

Ultimately, each state decides what machine it will use and how it will ensure the device provides reliable results. California breath testing requirements under Title 17 may be more stringent than other states and address many of the issues raised but issues still can exist. In most states, like California, drivers who refuse the test can face additional penalties which can include mandatory loss of license and increased jail time if convicted. However, it is important to note judges are speaking out against the use of these devices in some states. Judges in Massachusetts and New Jersey have made it clear they do not always trust these devices. These courts have thrown out over 30,000 breath tests over the last 12 months, citing issues like human error and a failure to properly oversee the calibration, use and storage of the devices.

As a result, those who face similar charges are wise to seek legal counsel to help determine if there are any defenses, issues with any breath or blood testing or mitigating factors. If not, there may be other defense options available.

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