In 2010, when a new person was brought in to run Washington, D.C.’s breath testing program, his first priority was to test the city’s Intoxilyzer machines for accuracy. He was astounded to discover that every machine was exaggerating the test results, entering numbers that were 20 to 40 percent higher than the actual result. This discovery likely implied that innocent drivers had been falsely accused of drunk driving for years.
An investigation into the problem revealed that the previous head of the program had routinely miscalibrated the machines. Moreover, the test chemicals used to initially calibrate the machines were expired and had lost their potency and were sometimes substituted with home-brewed alternatives.
The new department head pulled the machines from service and alerted the city’s top prosecutor that potentially years’ worth of DUI tests were exaggerated. The city will only acknowledged 18 months’ worth of problems. About 350 people were convicted of DUI in those 18 months, and all of their convictions are now subject to review.
The problems with Washington, D.C.’s Intoxilyzer machines were detailed by the New York Times in a major news investigation. Unfortunately, the Times also documented similar problems in jurisdictions all around the country. And, there’s good reason to suppose that these problems are routine — the result of simple human error, in many cases.
In just two states, Massachusetts and New Jersey, some 42,000 convictions are currently under review due to problems with their breathalyzer machines.
How many people are affected?
Every year, about a million people are arrested for drunk driving in the United States. How many of them will be convicted based on inaccurate breath tests?
It’s hard to tell, because many jurisdictions consider roadside breathalyzer tests to be preliminary. The roadside test provides probable cause for arrest and for an additional test. This additional test is either an official breath test at the police station or a blood test. Ideally, these more official tests would simply confirm the roadside breath test.
It’s when the official tests disagree with the roadside test that problems arise. If the roadside test was invalid due to negligence or misconduct, it should never have been used to justify an arrest.
Moreover, many DUI defendants plead guilty without bothering to challenge the test results. That makes it hard to know whether their breath test results were accurate.
The Times didn’t specifically allege that Tennessee is using miscalibrated or improperly set up devices, but it makes clear that these problems have been repeated from jurisdiction to jurisdiction.
The takeaway for drivers is this: Always fight your DUI charge, especially if you have reason to suspect the breath test result was too high.