CL
Written & reviewed by Charles E. Liken Jr., Esq.Colorado Attorney Since 2003 · Deputy District Attorney (2018–2020) · 700+ investigations · Reviewed for accuracy as of July 2026
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.