They get you any way they can with a full refusal, which is automatic revocation of your drivers license, but also if you blow a DWAI or DUI they confiscate your license and revoke it. So blood test is the way to go, but they're trying to remove the ability of you to choose which chemical test to take, because a blood test takes a few days and therefore they can't automatically revoke your license, they have to go to court and have a judge rule on that issue. So yes, you can refuse the roadsides and request a chemical test, but if you refuse all tests they automatically take your license for a year and it's a bitch to get back. The threshold for DWAI is pretty low, and if you're a heavy drinker and have a tolerance they get you for having excessive alcohol content, even if you're not impaired. And yes, most states require the tests to be administered by a cop with a specific certification. Also, a motorized wheelchair or moped is included in "motorized vehicle." If you're disabled, you can't legally operate your wheelchair when drunk. The best chance to beat a DUI is to refuse all tests and go to jury trial, but few people can afford the lawyer's fees and not being able to drive for a year. Revocation for refusal is not overturned on a not guilty verdict. If you ever find yourself charged with DUI, hire a DUI lawyer, one with a good reputation. They're very pricey, but I knew one who had a 75% acquittal record, so that would be worth it if a conviction would threaten your livelihood.