A million Americans a year are arrested for drunken driving, and most stops begin the same way: flashing blue lights in the rearview mirror, then a battery of tests that might include standing on one foot or reciting the alphabet.
What matters most, though, happens next. By the side of the road or at the police station, drivers blow into a miniature science lab that estimates the concentration of alcohol in their blood. If the level is 0.08 or higher, they are all but certain to be convicted of a crime.
But those tests — a bedrock of the criminal justice system — are often unreliable, a New York Times investigation found. The devices, found in virtually every police station in the U.S., generate skewed results with alarming frequency, even though they are marketed as precise to the third decimal place.
Judges in Massachusetts and New Jersey have thrown out more than 30,000 breath tests in the past 12 months alone, largely because of human errors and lax governmental oversight. Across the country, thousands of other tests also have been invalidated in recent years.
The machines are sensitive scientific instruments, and in many cases they haven’t been properly calibrated, yielding results that were at times 40% too high. Maintaining machines is up to police departments that sometimes have shoddy standards and lack expertise. In some cities, lab officials have used stale or homebrewed chemical solutions that warped results. In Massachusetts, officers used a machine with rats nesting inside.
Technical experts have found serious programming mistakes in the machines’ software. States have picked devices that their own experts didn’t trust and have disabled safeguards meant to ensure the tests’ accuracy.
The Times interviewed more than 100 lawyers, scientists, executives and police officers and reviewed tens of thousands of pages of court records, corporate filings, confidential emails and contracts. Together, they reveal the depth of a nationwide problem that has attracted only sporadic attention.
A county judge in Pennsylvania called it “extremely questionable” whether any of his state’s breath tests could withstand serious scrutiny. In response, local prosecutors stopped using them. In Florida, a panel of judges described their state’s instrument as a “magic black box” with “significant and continued anomalies.”
Even some industry veterans said the machines should not be de facto arbiters of guilt. “The tests were never meant to be used that way,” said John Fusco, who ran National Patent Analytical Systems, a maker of breath-testing devices.
Yet the tests have become all but unavoidable. Every state punishes drivers who refuse to take one when ordered by a police officer.
The consequences of the legal system’s reliance on these tests are far-reaching. People are wrongfully convicted based on dubious evidence. Hundreds were never notified that their cases were built on faulty tests.
And when flaws are discovered, the solution has been to discard the results — letting potentially dangerous drivers off the hook.
A Fateful Trip
The Deerfield River snakes through the woods of northwestern Massachusetts, and on a hot Sunday in July 2013, it was packed with rafters. Matthew Mottor arrived with more than a dozen friends and family members and two coolers of Blue Moon beer.
They spent hours tubing down the river and drinking before going ashore for a picnic. That’s when a drunk woman in the group caught the eye of a Massachusetts State Police trooper patrolling the area. The trooper, Steven Hean, told them to get their friend home. The party over, Mottor left his girlfriend and got a ride to his truck a few miles upriver.
He pulled his gray Dodge Durango onto the winding road. He made it about 200 yards. Then he saw the flashing lights.
Hean wrote in a report that he stopped Mottor for driving 41 mph in a 25 mph zone. Detecting “a strong odor” of liquor on Mottor’s breath, the trooper asked him to perform some field sobriety tests, including walking heel to toe.
Accidents years earlier had left Mottor with metal plates in his ankles and feet, court records show. “I explained to him that I’m not great at walking around on two feet on an everyday basis,” Mottor said. After passing two tests — reciting the alphabet and standing on one leg — he struggled to walk in a line. Hean brought out his breath tester.
Hand-held devices like Hean’s Alco-Sensor IV contain fuel cells that react to alcohol in exhaled breaths and generate an electric current — the stronger the current, the higher the alcohol level. They are inexpensive and easy to maintain, but their results can be inconsistent. Older women sometimes have trouble producing enough breath to get the machines to work. Toothpaste, mouthwash and breath mints — even hand sanitizer and burping — may throw off test results.
Tests from those portable machines are not admissible in court in most states (California is among the exceptions). But they often trigger an arrest, which leads to a test on another machine at the police station. That result determines whether someone is charged — and, often, whether they’re convicted.
By the side of River Road, Mottor blew a 0.13, far above the legal limit. That’s when the cuffs came out.
Near the end of Prohibition, a biochemist invented a suitcase-size machine with vials of chemicals and a balloon to blow into. Alcohol in the driver’s breath would trigger a reaction: the drunker the driver, the deeper the chemicals’ color. It was called the Drunkometer. But it was bulky and hard to use.
Two decades later, a police photographer and amateur chemist named Robert Borkenstein developed a similar but more portable machine. He named it the Breathalyzer.
Police departments around the country bought Borkenstein’s invention and versions developed by competitors. Then, in 1980, a fatal collision led to an overhaul of the U.S.’ drunken-driving laws — and a sales boom for companies that made breath-testing devices.
Carime Lightner, 13, was walking to a church carnival in Fair Oaks, Calif., when a drunken driver slammed into her so hard, she was knocked out of her shoes. The man had been arrested repeatedly for intoxicated driving.
Carime’s mother started Mothers Against Drunk Driving and launched one of the most effective citizen lobbying campaigns in history. States set stiffer penalties, including mandatory jail time in some cases, and made it illegal to drive with a blood-alcohol level above a designated mark.
The crackdown worked. In 1982, the year the National Highway Traffic Safety Administration began keeping records, some 21,000 people were killed in drunken-driving incidents. The number of deaths tumbled to around 10,500 in the most recent annual tally, even as the number of miles driven by Americans has nearly doubled.
In most of the country, the threshold for illegal drunkenness is 0.08 grams of alcohol per 100 milliliters of blood. The only way to measure that directly is to draw blood, which requires a warrant. Breath tests are simpler.
Testing machines can go for $10,000 or more, and some two dozen companies sell them in the United States. The biggest contracts, with state police crime labs, are worth millions.
A St. Louis company, Intoximeters, made the portable device used on Mottor. Dräger, a German company, owns the rights to the Breathalyzer name. CMI, based in Kentucky, is another industry leader.
“Our top priority is the quality and safety of our products,” said Brian Shaffer, a Dräger spokesman. “Our products provide the highest level of forensic and legal integrity.” He added, “Our advanced, evidential breath-alcohol-testing instruments exceed the requirements of national and international regulatory agencies.”
CMI and Intoximeters did not respond to multiple requests for comment.
Starting to Panic
Shirtless and still in swim trunks, Mottor arrived at the police barracks in Cheshire, Mass. He didn’t think he was drunk. But he was starting to panic.
He had left his phone in his SUV and had no way to tell his girlfriend what had happened. He pictured her alone by the river, thinking he had driven into a ditch.
Mottor was escorted to the station’s breath-testing machine. It was larger, more sophisticated and in theory more reliable than Hean’s portable instrument, and its results were admissible in court. Hean asked Mottor to start blowing. Hoping it would help him get back to his girlfriend faster, he complied.
The Alcotest 9510, manufactured by Dräger, resembles a fax machine with a small hose. As a person breathes into the device, a beam of infrared light is shot through the sample. Chemicals, including the ethanol in alcoholic drinks, absorb light to varying degrees. By analyzing how much light is absorbed, the instrument can identify the type of chemical and the amount of it present.
Many machines, including the Alcotest 9510, also use a fuel-cell sensor — the same type of tool that is in portable devices. Each system is supposed to operate independently; if both return similar results, the theory goes, it’s an extra assurance that the measurement is accurate.
Mottor blew for about 10 seconds, the machine beeped, and a number flashed on its screen: 0.08.
He was charged with operating under the influence, which leads to the automatic revocation of driving privileges in Massachusetts. Hean confiscated Mottor’s license and called a truck to tow his SUV.
Breath-testing machines need less than a minute to run their calculations. What happens during those 60 seconds, though, has been the subject of years of courtroom fights.
Defense lawyers have repeatedly tried to forensically examine the machines, especially their software. Inspecting the code could reveal any built-in flaws or assumptions the devices use in their calculations.
But even procuring a machine is a challenge. Manufacturers won’t sell them to the public.
Courts in at least six states, including New York, have rebuffed defense lawyers’ attempts to get their hands on the machines’ code.
But in 2007, the New Jersey Supreme Court granted a request by defense lawyers and ordered Dräger to allow outside experts to analyze the software for the Alcotest 7110 machines in use statewide. Experts said it was littered with “thousands of programming errors,” according to their report to the court.
After reviewing the evidence, the court deemed the Alcotest 7110 “generally scientifically reliable.” But the state court also acknowledged the devices had “mechanical and technical shortcomings” that had the potential to produce the wrong result. Dräger said it quickly fixed the problems, but the state never rolled out the software update, court records show. Dräger now advertises the 7110 as the only device on the market whose software “has been reviewed by independent third parties and approved by a Supreme Court decision.”
None of that made a difference in other states, which employ a variety of machines and standards. Each state decides how rigorously it will test machines, and several have used devices that were deemed unreliable elsewhere.
‘Throw Caution to the Wind’
When the state of Washington decided to spend more than $1 million to replace its aging machines in 2009, state police chose the Alcotest 9510 despite a report by their own scientist that described the machines as “not yet ready for implementation.”
Before rolling out the machines, state officials debated whether to spend tens of thousands of dollars on an outside expert to evaluate the software. Fiona Couper, a state toxicologist, emailed her colleagues: “I think we throw caution to the wind and proceed without paying upfront for an independent evaluation.” (In an email to the Times, Couper said that “it was too premature to evaluate the software at that time.” Court records show no evaluation was ever done.)
In 2015, a local judge granted a request from defense lawyers to review the software underpinning the state’s Alcotest machines. That task fell to a consulting company run by two veteran programmers and security experts, Robert Walker and Falcon Momot.
Walker had worked at Microsoft for more than a decade and was adept with Windows CE, the obsolete operating system powering the Alcotest 9510. Momot, a soft-spoken hacker with spiky facial piercings and a rainbow-colored mohawk, was known for his talent in hunting down complicated computer bugs and software vulnerabilities.
After a couple weeks dissecting the Alcotest code, they wrote a nine-page draft report, “Defective Design = Reasonable Doubt.” They planned to dig further, but things went awry when they shared their report with defense lawyers at a convention.
Dräger sent Walker a letter demanding that he and Momot ask anyone with a copy of their report to destroy it — including the lawyers who hired them — and to stay silent about the instruments’ inner workings. Facing a giant company, Walker felt he had no choice but to comply. “I am an ant,” he said.
Shaffer, the Dräger spokesman, said the company was defending its intellectual property. “We really have nothing to hide, but we have something to protect,” he said.
Although Momot and Walker’s preliminary report never made it into court, a few copies survived. The Times obtained one from a defense lawyer.
The report said the Alcotest 9510 was “not a sophisticated scientific measurement instrument” and “does not adhere to even basic standards of measurement.” It described a calculation error that Walker and Momot believed could round up some results. And it found that certain safeguards had been disabled.
Among them: Washington’s machines weren’t measuring drivers’ breath temperatures. Breath samples that are above 93.2 degrees — as most are — can trigger inaccurately high results.
Washington had decided against spending more on a sensor that would check breath temperature and allow the software to adjust for it, according to Shaffer. He said Washington wasn’t alone; most of Dräger’s U.S. clients skip the sensors.
‘Serious Errors of Judgment’
As Mottor’s case inched along in Massachusetts, a parallel legal fight was playing out: Lawyers representing hundreds of drunken-driving defendants were pelting the state’s courts with requests for more information on the Dräger Alcotest 9510. (Their cases were consolidated into a single action.)
In 2016 — three years after Mottor was pulled over — the state’s highest court ruled that Massachusetts had to hand over two Alcotest machines. The defense lawyers would be allowed to hire experts to test them.
The decision caused paralysis. Prosecutors froze thousands of cases until the review was finished.
Software experts and scientists who inspected the Alcotest 9510 machines found troubling mistakes, according to their reports to the court. In some circumstances — when the devices’ two testing methods produced substantially different results, for example — the machines were supposed to generate error messages and terminate the test. Instead, the devices printed a result. (Dräger blamed an error by its computer programmers, which it said has now been fixed.)
But the machines weren’t the only problem. The Massachusetts forensic lab, which for years had been plagued by scandals over faked drug test results and tampered evidence, lacked a written procedure to set up and test machines, the lab’s technical director testified.
The justice hearing the case, Robert Brennan, said the lab could not prove that it had followed a “scientifically sound methodology,” and in 2017 he threw out all of its breath test results from 2012 through 2014.
That was only the beginning. Lawyers soon discovered that the lab had hidden records of hundreds of failed calibrations. The discovery provoked a state investigation that blasted the lab’s leadership for “serious errors of judgment.”
Brennan later expanded his previous order: No tests from the lab were admissible until it was accredited by a national board that oversees forensic labs. Eight years of tests — more than 36,000, according to defense lawyers — were suddenly off-limits.
Mottor’s trial finally got underway Jan. 10, 2018. He and his lawyer didn’t realize that his breath test was among those that had been invalidated. It remained the state’s crucial piece of evidence.
His lawyer told the court about Mottor’s shaky balance and metal-filled feet, but the arguments didn’t resonate. The only thing that seemed to matter to the jury was the breath test.
“The .08 comes in, and to them, that’s a conviction,” Mottor said. He was found guilty.
A couple of weeks later, he learned that his breath test never should have been part of the prosecution. He asked to have his case reopened.
When Mottor’s request was granted, the prosecutor made him an offer: Plead guilty to a lesser offense, and the drunken-driving charge would be dropped. In February, more than five years after his arrest, Mottor took the deal.
“Even the people in the clerk’s office were high-fiving me afterward,” he said. “They were happy that it was over.”
Since his arrest, Mottor has maintained a clean driving record. He is still paying off the roughly $30,000 he accrued in fines, court fees and legal bills.
“If we are going to put people in jail and punish people, take their liberties away, take their licenses away, we have an obligation to be accurate,” said Joseph Bernard, the defense lawyer who helped Mottor get a new trial and is representing dozens of others in Massachusetts.
But there is a cost. Throwing out tens of thousands of faulty breath tests will inevitably let some dangerous drivers back on the road.
“Let’s not fool each other,” Bernard said. “I am not going to sit here and tell you that situation and that dynamic isn’t going to happen. Of course it’s going to happen. The question is, whose fault is it?”