Testing do-it-yourself Breathalyzers

By Jaie Avila

SAN ANTONIO - There's only one sure way to get home safely from this year's Fiesta events: Don't get behind the wheel if you've had anything to drink. Instead call a cab or bring a designated driver.

But what about those portable Breathalyzers you can now buy? They claim to be able to tell you if you are "still safe" to drive.

News 4 Trouble Shooter Jaie Avila put some of those devices to the test by comparing them to the Intoxilyzer many police departments use. Those Intoxilyzers are calibrated regularly and the results are admissible in court.

Let's not lose sight of why we're talking about this: the idea is to prevent tragedies like the one that happened to Danny Slape. Fourteen years ago he was struck by a drunk driver while walking on the street.

Slape almost died from his injuries, and to this day, he needs to post stick-it notes around his apartment to remind him to do simple things like turn off the oven, or lock the front door.

"DWI's are 100% preventable. Nobody wants to live like I live," Slape says.

Could those personal Breathalyzers help prevent crashes by warning drivers when it's no longer safe to get behind the wheel?

We bought four of them on the internet. They range in price from $116, down to $25 for one that goes on your keychain.

Assisting us with the test was Corporal Jose Davila, who has been running Intoxilyzer tests for the Castle Hills Police Department for nine years.

First Davila has our two test subjects blow into the Intoxilyzer before they drink any alcohol. Sure enough the results show no alcohol in their systems. We do the same with the Breathalyzers we purchased. All show their blood alcohol levels at zero.

Our female volunteer drank five-ounce glasses of wine, while the male subject drank 12-ounce bottles of beer.

In less than an hour, our wine drinker finishes two glasses, and the other volunteer has polished off three beers. Then we took the first test. The female subject was tested with the police Intoxilyzer to see how close her blood alcohol level was to the legal limit of .08.

The Intoxilyzer shows her blood alcohol content at .04, about half way to legal intoxication. The male subject tests a little bit lower, at .03.

Then both volunteers were tested using the Breathalyzers we bought. Surprisingly, the first three gave higher readings than the police Intoxilyzer. The keychain model even showed our volunteers already at the legal limit of .08.

Only the last device, a Breathalyzer that plugs into your iPhone, failed to detect the presence of alcohol.

"This one says I have a blood alcohol level of zero," said our female volunteer.

We followed the directions, but we couldn't get that model to take a reading.

Corporal Davila says that's one of the problems with self-testing: if we're having trouble working a device, how difficult would it be for someone who is drunk?

"My personal take on it is, if you have to resort to using an instrument like that, then you obviously shouldn't be driving," Davila told us.

The volunteer's kept drinking until the female subject had finished four glasses of wine, and her companion put away six bottles of beer, all within a two-hour period.

At that point the police Intoxilyzer showed they were both legally drunk: a reading of .09 for her, and .081 for him.

Just as before, three of the Breathalyzers we purchased showed readings that were even higher. The highest putting the female's blood alcohol level at .11 and the male volunteer's at .10.

Once again the iPhone Breathalyzer was the only device to give a result that was too low: it showed the female subject at only .05 and the male volunteer at zero, even though they were both over the legal limit.

Apple doesn't make that device. We tried contacting the company that sold it to us, but we got no response.

A company called BACtrack, which makes two of the devices we tested told us: "We've done user research and found that simply by owning and using a Breathalyzer, it reduces the incidents of impaired driving because you are talking about it and are aware of your alcohol level."

That's something Danny Slape agrees with.

"If they're accurate, I think they'd be great, if you can get people to use them," Slape says.

Three of the four Breathalyzers did pretty well on the test. The manufacturers tell us they purposely calibrate their devices at the factory to be more sensitive and give higher readings.

"If the results are going to skew, skewing higher is better," said the maker of the AlcoHawk device we tested.

But over time any Breathalyzer will go out of calibration, that's why the police have their Intoxilyzer checked frequently.

Depending on the model of device you buy, some manufacturers will allow you to ship it back to be re-calibrated.

Видео Testing do-it-yourself Breathalyzers канала News 4 (WOAI) San Antonio