What Can Invalidate a DWI Stop in San Antonio?

The Fourth Amendment and San Antonio DWI Stops

A DWI traffic stop in Texas requires reasonable suspicion — a specific, articulable fact that the officer believed indicated a traffic violation or criminal activity. Under Rodriguez v. United States (575 U.S. 348, 2015) and Texas CCP Art. 38.23, if the stop lacked that legal basis, or if SAPD extended the stop beyond its original traffic purpose without independent suspicion, everything discovered during the investigation is suppressible. No valid stop means no DWI investigation, no breath test result, no case.

Insufficient Basis for the Original Stop

Most DWI stops in San Antonio originate from an alleged traffic violation. Common claimed violations on IH-10, IH-35, Loop 1604, the River Walk corridor, and Culebra Road include failure to maintain a single lane, speeding, equipment violations, improper lane change, and running a red light. We pull SAPD dashcam and bodycam footage the day we are retained and compare it frame-by-frame against the officer’s written report. When the video shows driving that does not constitute a violation under the Texas Transportation Code, a suppression motion under Art. 38.23 is filed at Cadena-Reeves.

Extension of the Stop Beyond Its Original Purpose

Under Rodriguez v. United States, even a lawfully initiated traffic stop cannot be extended beyond the time reasonably needed to address the original traffic violation without independent reasonable suspicion of criminal activity. If SAPD’s stated basis was a minor equipment violation, they cannot detain the driver indefinitely fishing for DWI indicators. The moment the extension of the stop lacks justification, everything discovered after that point is suppressible regardless of what BAC was found.

Anonymous Tips and Third-Party Reports

An anonymous tip about a drunk driver can provide the basis for a stop, but only if the tip has sufficient indicia of reliability under Florida v. J.L. and Navarette v. California. A bare anonymous tip without corroboration is typically insufficient. We examine the SAPD dispatch log and any recorded tip on every stop that originated from a third-party report.

Why the Stop Analysis Is Where San Antonio DWI Cases Are Won

The stop analysis is the first thing we do on every San Antonio DWI case. A successful suppression of the stop makes all other evidence challenges unnecessary. If the stop falls, the case ends — regardless of what the breath test showed or how poorly the defendant performed on the SFST.