[Richard]

I don't know for sure either but I thought they had to road side you then have you blow withing a time frame then like herbie said do it again to see if the sample goes up or down to establish an impairment time line.

[andyt]

Again - AFAIK the roadside units are not considered reliable enough for a criminal charge. They have to take you back to the cop shop and then AFAIK wait a bit until they administer the test. She blew .06 on a roadside unit, so the cops had no reason to take her to the cop shop for a full on test. She was convicted based on her statements she made to an undercover cop that pretended to be her friend.

If you're smart, you'll carry a bottle with you, and if you hit somebody take a few hits of it. Tell the police you needed it to steady your nerves. We had an off duty RCMP who killed a kid, ran home and then returned to the scene of the accident. He said he had a few belts of vodka while home to steady his nerves. They could not convict him of DUI, and he got a slap on the wrist. This is one of the cops that was involved with the tazering death of that Polish guy. Nice, eh?

[Brenda]

AFAIK, only a blood test is reliable enough to hold up in court when it has to be determined how much exactly was in your blood.

[Richard]

My bad I thought you had said she blew .06 three hours later. Then waited for the second test and blew .04. I found this page it gives a run down.
http://www.canadianlawsite.ca/impaired-driving.htm#b