Failure to Maintain a Single Marked Lane: Challenging Texas DWI Stops
Updated: Oct 27
Late at night along the Katy Freeway, Highway 59, or the Westpark Tollway, patrol officers often trail a vehicle for miles waiting for a pretext to pull it over. They are not pulling you over because they know you are intoxicated; they are trailing you waiting for a single tire to drift onto a lane marker or momentarily touch the shoulder fog line.
Within seconds, the emergency lights flash. The officer approaches your window and announces the reason for the stop: "You failed to maintain a single marked lane."
For years, law enforcement treated any momentary touch of a painted stripe as an open ticket to initiate a roadside DWI investigation.
However, Texas law does not give police unlimited discretion to stop drivers for minor drift. Under landmark rulings from the highest criminal court in Texas, a driver who drifts within or slightly outside their lane has not necessarily broken any law. If the initial traffic stop was unlawful, the Fourth Amendment mandates that every piece of evidence gathered afterward—field sobriety tests, breath scores, and blood vials—must be completely suppressed.
The Statutory Elements: Texas Transportation Code § 545.060
Officers frequently cite Texas Transportation Code § 545.060 as justification for pulling over suspected impaired drivers. But reading the actual statutory language reveals that the law requires far more than simply touching a painted line.
Under Section 545.060(a), an operator on a roadway divided into two or more clearly marked lanes for traffic:
Shall drive as nearly as practical entirely within a single lane; and
May not move from the lane unless that movement can be made safely.
[ OBSERVED VEHICLE LANE DEVIATION ]
│
┌─────────────────────────────┴─────────────────────────────┐
▼ ▼
[ Drift / Stripe Touch ONLY ] [ Unsafe Movement ]
• Tire touches white dash line • Cuts off adjacent vehicle
• Brief cross over fog line onto shoulder • Causes another car to brake or swerve
• No other vehicles endangered • Erratic swerving across multiple lanes
│ │
▼ ▼
[ NO STATUTORY OFFENSE ] [ STATUTORY VIOLATION ]
• Fails Section 545.060 requirements • Satisfies Section 545.060
• Stop violates Fourth Amendment • Valid reasonable suspicion for stop
• DOWNSTREAM EVIDENCE SUPPRESSED • Lawful investigative detention
For decades, prosecutors argued that these were two separate, independent offenses: that failing to remain entirely within a single lane was a violation by itself, regardless of whether it created any danger.
That interpretation allowed officers to execute pretextual stops on sober motorists whose tires drifted by a few inches on curved freeway ramps or construction corridors.
The Landmark Precedent: State v. Hardin
In 2022, the Texas Court of Criminal Appeals issued a definitive ruling in State v. Hardin (664 S.W.3d 867) that fundamentally altered how Texas courts evaluate lane-deviation traffic stops.
The Court resolved decades of conflicting appellate decisions by interpreting the plain text of Section 545.060:
Failing to drive as nearly as practical within a single marked lane is not a criminal offense unless the State also proves that the movement was made unsafely.
Under Hardin, touching or crossing a lane line does not automatically provide an officer with reasonable suspicion or probable cause. If a driver touches the center stripe or drifts onto the shoulder, but there are no other vehicles in close proximity, no collision hazard, and no erratic corrections, no traffic violation has occurred.
An officer's subjective belief that you committed an offense does not save an illegal stop. If the driving behavior did not violate the statute, the officer lacked the constitutional authority to detain you in the first place.
Pretextual Stops vs. General Suspicion of Intoxication
Police officers frequently argue an alternative theory when challenged under Hardin: even if there was no strict statutory violation of Section 545.060, the weaving gave them "reasonable suspicion" to believe the driver was intoxicated.
Texas courts reject this blanket justification. Under the Fourth Amendment:
Reasonable Suspicion requires specific, articulable facts that, combined with rational inferences, lead an officer reasonably to conclude that criminal activity is afoot.
A single instance of drifting, weaving within the boundaries of a single lane, or touching a line does not establish reasonable suspicion of Driving While Intoxicated.
Driving late at night is not a crime. Adjusting a radio, navigating construction barrels on the 610 Loop, or naturally compensating for roadway grooves routinely causes minor lane variations in completely sober drivers. Without corroborated signs of dangerous impairment—such as driving into oncoming traffic, severe fluctuations in speed, or near-collisions—routine lane touches remain legally insufficient to justify seizing a citizen on a Texas roadway.
The Exclusionary Rule: Texas Code of Criminal Procedure Art. 38.23
When a police officer conducts an unconstitutional traffic stop, the legal remedy in Texas is absolute.
Under Texas Code of Criminal Procedure Art. 38.23, Texas maintains a statutory exclusionary rule that exceeds federal constitutional protections:
"No evidence obtained by an officer or other person in violation of any provisions of the Constitution or laws of the State of Texas, or of the Constitution or laws of the United States of America, shall be admitted in evidence against the accused on the trial of any criminal case."
This is the codification of the "fruit of the poisonous tree" doctrine. If defense counsel proves at a pretrial evidentiary suppression hearing that the officer lacked legal justification to initiate the stop under Section 545.060 and State v. Hardin, every subsequent evidentiary development is deemed legally tainted.
Evidence Collected After an Illegal Stop | Impact of Granted Motion to Suppress |
Officer Observations of Odor & Slurred Speech | Stricken from the record / Inadmissible |
Field Sobriety Tests (HGN, Walk-and-Turn) | Excluded from trial entirely |
Preliminary Breath Tests & Roadside Statements | Suppressed / Cannot be heard by a jury |
Chemical Blood Warrants or Station Intoxilyzer Results | Inadmissible in court |
Without the stop, there is no detention. Without the detention, there is no arrest. Once the judge suppresses the evidence, the State is left with no legal basis to proceed, forcing an outright dismissal of all criminal charges in Harris County courtrooms.
Dismantling the Stop with Dashcam Video
Winning a motion to suppress based on an improper lane-change stop requires precise forensic scrutiny of the State's own video evidence.
When our firm takes on a DWI case originating from a traffic stop, we do not accept the narrative written in the offense report. We subpoena the officer's cruiser dashcam and forward-facing video:
The Lead-Up Footage: We review the minutes preceding the stop to measure how many times the tires approached the lines, the exact width of the roadway, and whether passing traffic was affected.
Proximity of Other Motorists: We establish whether there were any other vehicles within striking distance that could have been endangered by the vehicle's movement.
Cross-Examining the Officer: Under oath, we force the arresting officer to admit that the movement was gradual, that no other cars braked or swerved, and that the driving maneuver was entirely safe.
If you were pulled over for touching a white line or momentary weaving, your case should be fought at the initial stop level before any chemical test is ever considered. Discover how we challenge unlawful roadside detentions across our Houston DWI defense legal services.
Was Your Houston DWI Arrest Based on a Questionable Lane Stop?
Police officers cannot pull you over on a hunch. If an officer claimed you failed to maintain a single marked lane without proving an unsafe hazard, your stop may have violated Texas law and the Fourth Amendment. An illegal stop can destroy the prosecution's entire case.Schedule a Confidential Case Review online, or call our Houston defense team directly at (713) 714-7330 to audit your cruiser dashcam video today.
Community Discussion
Under the Texas Court of Criminal Appeals ruling in State v. Hardin, an officer cannot lawfully pull you over for simply touching or crossing a lane stripe unless the maneuver endangered someone. Despite this ruling, police regularly use minor tire drift as an excuse to stop late-night drivers and search for alcohol. Do you think officers who conduct traffic stops without an actual safety hazard should face disciplinary action for violating constitutional rights? Share your thoughts in the comments below.
