To assess the Guardian Angel, as well as a $50 purse-size breathalyzer (the PSI BT5500) from Sharper Image, NEWSWEEK enlisted the help of a government official. He brought along the Alcotest 7410 Plus, a $2,000 machine used by police. Three NEWSWEEK volunteers drank for two hours, comparing readings on all three test systems. Hardly scientific, but here’s our general advice:
It’s an Estimate: You probably shouldn’t base a decision to drive solely on the results. (The manufacturers say it’s never smart to drink and drive; Tip Sheet agrees.) However, after moderate consumption, the two lower-priced tests approximated the Alcotest 7410 results.
Follow the Directions: The saliva strips call for a 10-minute wait after drinking; the $50 unit suggests a 30-minute pause. Ignoring the instructions skewed the results.
Don’t Judge Yourself: The more the volunteers drank, the more difficulty they had performing and interpreting the tests. Let someone sober read the results.
Lower Limits: None of our test subjects say they’d feel safe driving with a blood alcohol content remotely near the legal limit–usually 0.08. The bottom line: trust a designated driver before any gadget.
