DWI – Admissibility of Breath and Blood Tests

CHEMICAL TESTS in a DWI(Breath, Blood, Urine)

The State has the burden of proving a Defendant is guilty of a DWI. If using a chemical test, they must prove they are above 0.08.

Consent needed: By law, a person can refuse all tests requested by the police. The consent to take a test must be shown to be voluntary.

The State has the burden to show by “clear and convincing” evidence that the test was voluntary. Things the Court consider are:
1) if the police claim authority,

2) show of force / coercive surroundings,

3) threatening to seek / obtain a search warrant,

4) deception of identity / purpose,

5) prior unlawful police action,

6) if Miranda warnings given,

7) if defendant was aware of Fourth Amendment rights,

8) confessions or other cooperation,

9) denial of guilt,

10) defendant’s maturity, sophistication, andemotional or mental state.

Mandatory Specimens:
A police officer MAY force a person to take a blood or breath test if they are arrested for a DWI involving a death or serious injury accident.

1) Breath Tests:
Most tests are done with Breath tests. To be admissible, the State must

1) use proper compounded chemicals in the machines reference solution,

2) conduct periodic supervision with someone who is trained in the science of the machine,

3) provide a witness to the test, so its admissible,

4) prove certification of the test operator,

5) prove that the breath’s chemical analysis was done pursuant to DPS rules.

2) Blood Tests:
The most accurate test is the blood test. To be admissible, a blood test must:

1) show the blood was taken by order or request of a peace officer,

2) show the defendant’s consent,

3) the blood was withdrawn by a proper person,