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Volpe's Unique Simulator Revolutionizes Breathalyzer Evaluation

Wednesday, July 3, 2013

Volpe's Ed Conde, Art Flores, and Alan Kauffman spend their days testing blood alcohol detection devices to identify the highest caliber products for federal, state, and local law enforcement and transportation personnel. Working in the Alcohol Countermeasures Laboratory at Volpe, The National Transportation Systems Center, Conde, Flores, and Kauffman use a breath alcohol sample simulator, called BASS, to evaluate alcohol detection devices for conformance with the National Highway Traffic Safety Administration's Model Specifications.

The BASS consists of a series of cylinders containing ethanol and water. Software directs the BASS to emit samples saturated with water vapor that are nearly identical to that of a human. Since water vapor can affect the results of a breath test, especially during hard-pressure blows, the addition of water vapor ensures that the test devices, as measured in the laboratory, perform the same way in the field.

With a recently-added computer control panel, staff can now precisely control the BASS. To evaluate evidential breath test (EBT) instruments under varying breath strengths, software parameters are set that cause the valves of the BASS to open and close to emulate a human's different breath pressures. The BASS's ability to manipulate the breath pressure ensures that the laboratory can establish an EBT's reliability in real-world conditions.

"By testing devices that come into this lab very rigorously, I know that each product that is deployed to law enforcement and transportation agencies will perform as intended in the field," said Conde. "I see the work we're doing as vitally important. We are obligated to protect the public from those individuals who are acting recklessly by drinking and driving. The work we're doing gives the American public the peace of mind that regardless of location, they won't be wrongfully accused of operating under the influence if they haven't been drinking."

The Alcohol Countermeasures Laboratory at a Glance

Volpe's Alcohol Countermeasures Laboratory—started in 1970 by Flores and run by Conde since 2001—is the primary NHTSA-recognized laboratory with the authority to test and approve alcohol-detection devices that are used by law enforcement or the transportation industry.

Building the BASS

During the BASS design and build process, it was important for the BASS to provide the precision and accuracy of the human breath under all circumstances, given normal human variability. Flores worked directly with the National Institute of Standards and Technology (NIST) to ensure that the technical components of the BASS met appropriate standards. Once the simulator was complete, Conde extensively tested the BASS, comparing its results to human test subjects. The BASS's results proved to Volpe and NHTSA that this simulator would enhance the lab's current offering and provide a more consistent testing protocol.

What Does It Take to Approve an Evidential Breath Testing Device?

Before an EBT device can be included in the NHTSA Conforming Products List, it must first undergo weeks of testing at the ACL. Many devices fail and must be improved before they comply with NHTSA's specifications. The devices that pass are added to NHTSA's Conforming Products List. Police and workplace personnel use this list to help ensure that they are buying instruments that will work well in the field. "The testing protocols and environment that we have here at Volpe are unique," said Conde. "Combining the unparalleled precision and accuracy of the BASS with other simulators like the shake table or temperature chamber, provides us with capabilities that most manufacturers don't have." 

Man taking a breathalyzer test