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DUI Center No. 4 · The Evidence

The Stop, the Tests, and the Evidence Against You

Roadside tests you could have refused, machines with maintenance logs, blood vials with chain-of-custody paperwork — the state's evidence is more attackable than it looks from the back of a patrol car.

Charles E. Liken Jr., Esq. — On Colorado's Legal Front Lines Since 1995 · Government Investigator, Denver Human Services (1997–2003) · Licensed Colorado Attorney Since 2003 ~ 20+ Years in Private Practice · Colorado Deputy District Attorney (2018–2020) · Colorado Court-Appointed Child and Family Investigator

Five places DUI evidence breaks

Every DUI file is a chain: stop → contact → roadsides → arrest → chemical test. A defensible weakness at any link changes the whole case. Finding those weaknesses is literally Charles's old job.

1

The stop itself

The officer needs reasonable suspicion for the stop and probable cause for the arrest. Weaving inside your own lane, anonymous tips, and “high-crime area” boilerplate all have case-law limits — and body-cam video often tells a different story than the report.

Where LLF comes in: We pull every video before retention windows lapse and time-stamp the report against it. Government investigators learn quickly: the paper and the footage rarely match perfectly.

2

Roadside maneuvers are voluntary — and subjective

In Colorado, roadside sobriety maneuvers (walk-and-turn, one-leg stand, HGN) are voluntary. If you did them, their validity depends on standardized administration, surface, footwear, weather, and your medical realities — all cross-examinable.

Where LLF comes in: Charles cross-examines SFSTs with the NHTSA manual in hand — scoring deviations and improper instructions convert “failed” into “unreliable”.

3

The breath machine is not an oracle

Evidentiary breath tests require certified devices, trained operators, and a proper 20-minute observation period. Calibration records, maintenance logs, and operator certifications are all discoverable — and imperfect. The result only creates an inference (§ 42-4-1301(6)(a), C.R.S.), never a verdict.

Where LLF comes in: We subpoena the machine's paper trail as a matter of routine. Files that look airtight on the report page get looser in the maintenance log.

4

Blood tests: science with paperwork

Under express consent (§ 42-4-1301.1(2), C.R.S.) you generally choose blood or breath for alcohol; suspected drug impairment means blood. Blood must be drawn, stored, transported, and tested to standard — vials ferment, labels err, and labs have audit histories.

Where LLF comes in: Chain-of-custody attacks are detail warfare. Seven hundred investigations of detail are on your side.

5

Rising BAC and the timing gap

Your BAC at the time of driving is the legal question; the test happens an hour or more later, while absorption may still be raising the number. The gap between driving and testing is a genuine scientific defense, not a trick.

Where LLF comes in: We reconstruct the drinking-and-driving timeline with receipts, witnesses, and toxicology consulting when the numbers justify it.

Ready when you are — talk it through with Charles.

Your choice: no-charge 20-minute phone call OR in-depth hour ($300) — both directly with Charles.

Quick answers

Do I have to do roadside sobriety tests in Colorado?

No — roadside maneuvers and the small preliminary breath test are voluntary for adult drivers. The evidentiary blood-or-breath test after arrest is governed separately by the express-consent law, § 42-4-1301.1, C.R.S., with license consequences for refusal.

Can a breathalyzer result be challenged?

Yes — certification, calibration, maintenance, operator training, and the required observation period are all attackable, and the result creates only a permissible inference under § 42-4-1301(6)(a), C.R.S.

What is a rising-BAC defense?

Alcohol keeps absorbing after you stop drinking, so a test taken an hour after driving can read higher than your level while driving — the legally relevant number. Timeline evidence can make that gap a real defense.

Is the officer's report the final word on what happened?

No. Reports are one participant's after-the-fact narrative. Video, dispatch logs, and cross-examination regularly contradict them — which is why preserving video immediately matters.

The Paper War

Discovery is where DUI cases are actually won

The state's case arrives as a package: reports, video, machine records, lab records, dispatch logs, training files. Most of it is only produced if someone asks precisely and early. That's the quiet difference between defense lawyers — not the closing argument, the document requests.

Charles built these packages for the government and charged cases off them as a Deputy DA. He knows which page is missing, which log contradicts which timestamp, and which omission means a motion — because omissions were his business.

Step by step

  • 1 · Preserve — Immediate video/records preservation letters — body-cam, dash-cam, booking, dispatch.
  • 2 · Demand — Complete discovery: machine logs, operator certs, lab accreditation and audit history.
  • 3 · Reconstruct — Timeline of driving, drinking, absorption, and administration vs. the report.
  • 4 · Move — Suppression and evidentiary motions where the links fail — leverage or dismissal.

“I failed the tests” is not the end of the analysis

People tell us daily that they failed the roadsides or blew over the limit, as if the case is over. The number is the beginning of the state's proof problems, not the end of yours.

Related: Charges & Penalties · How We Defend · Marijuana & Drug DUI. General information, not legal advice.
THE LONGMONT LAW FIRM
Charles E. Liken Jr., Esq.
Attorney & Counselor at Law

Say nothing. We'll do the talking.

Before you talk to anyone — DA, DMV, insurance — get twenty minutes with the prosecutor turned defender.