EDIT:
The law is complicated on this topic and it varies by region. I didn’t think this needed saying when I made the post, but this isnt an end all be all on the topic, it’s just something I found interesting & posted it to c/Today I Learned.
Don’t take legal advice from a Lemmy post. Talk to a lawyer.
The Purpose of Portable Breath Tests
Portable breath tests are commonly used by law enforcement officers to quickly estimate a person’s blood alcohol content (BAC) at the scene of a suspected DUI offense. These handheld devices are designed to provide immediate results, helping officers in their decision-making process during a traffic stop or investigation.
It is essential to understand that a portable breath test is different from the more accurate breathalyzer devices used at police stations or during formal chemical testing. While portable breath tests can provide an initial indication of a person’s intoxication level, they should not be considered as wholly accurate or infallible.
https://rhilllaw.com/blog/2021/03/can-a-portable-breath-test-be-used-in-court/
Where I live if you test positive with the portable one they make you wait 20 minutes and take a second test on a bigger machine. I’ve heard you can then challenge that second test with a blood test but they don’t usually end well.
Refusing to take the breath test will bring you penal charges.