California DUI attorneys' cases often focus on this relevant breath test regulation:
A breath sample shall be expired breath which is essentially alveolar in composition. The quantity of the breath sample shall be established by direct volumetric measurement. The breath sample shall be collected only after the subject has been under continuous observation for at least fifteen minutes prior to collection of the breath sample, during which time the subject must not have ingested alcoholic beverages or other fluids, regurgitated, vomited, eaten, or smoked. [ Title 17 - section:1219.3. Breath Collection ]
While the California case of Manriquez v. Gourley sometimes permits limited observation during the transportation time, California DUI criminal defense attorneys need to be aware of that case's distinctive criteria.
To obtain a better appreciation of the required observation, check out this helpful California DUI lawyer site's discussion of Manriquez v. Gourley (2003) 105 Cal.App.4th 1227 , 130 Cal.Rptr.2d 209.