Getting pulled over on I-64 near Forest Park or along Lindbergh Boulevard on a Friday night is stressful enough without wondering afterward whether the officer even had the right to stop you. But if you were recently arrested for DWI in St. Louis City or elsewhere in the metro, you shouldn’t assume that the police officer who did it conducted your traffic stop legally. From a legal standpoint, whether police had the right to pull you over shapes everything that happens next in your case.
Missouri law generally requires that an officer have what’s called reasonable suspicion before initiating a traffic stop. This standard matters more than most drivers realize. If that initial suspicion didn’t exist, everything the officer observed afterward, including field sobriety and breath tests used as evidence to arrest you, may become part of an effective DWI defense strategy. Our attorneys have challenged numerous DWI traffic stops with positive results.
What Reasonable Suspicion Actually Requires
Reasonable suspicion sits below probable cause (the required standard for arresting somebody), but it requires more than a hunch. An officer patrolling I-70 through north St. Louis or working a late shift near the Delmar Loop needs to be able to point to something specific that they observed: speeding, weaving between lanes, a broken taillight, failure to signal, or driving significantly under the limit.
Missouri courts have looked closely at borderline situations over the years. Touching the fog line once, for example, has sometimes been found insufficient on its own to justify a stop. But combine that with weaving, erratic braking, or crossing the centerline more than once, and courts often view the totality of those facts differently.
That phrase, totality of the circumstances, comes up constantly in these cases. Judges don’t look at one moment in isolation. They look at the whole picture the officer says he or she observed.
How This Plays Out During a Real Stop
So picture this: it’s a Saturday night, traffic is backed up near Busch Stadium after a Cardinals game, and an officer notices a car drift twice within its lane. That alone might be thin. Add in braking for no apparent reason and a delayed reaction to a green light, and now there’s a stronger argument for reasonable suspicion. Once the stop happens, the officer’s questioning and observations are supposed to stay tied to the reason for the stop, unless the unrelated questions don’t measurably prolong the stop or reasonable suspicion of another crime arises. If the officer smells alcohol, notices slurred speech, or sees an open container, that can shift things toward probable cause for a DWI investigation and eventually an arrest.
About those checkpoint stops… Missouri does allow sobriety checkpoints when properly operated and publicized in advance, and we sometimes see them set up around Soulard during Mardi Gras season or near The Hill on busy weekends. Checkpoints follow a different legal framework than a routine stop, since individualized suspicion isn’t required the same way. That’s a topic worth its own discussion another time.
How Defense Attorneys Use the Evidence
This is the part that matters most for you. When we take on a DWI case out of St. Louis County Circuit Court in Clayton or the City of St. Louis Circuit Court downtown, one of the first things we do is pull the dashcam footage, body camera video, dispatch audio, and the officer’s written report. Then we compare all of it against what the officer claims justified the stop.
Sometimes the video shows smooth, steady driving with no visible violation at all. Sometimes the officer’s report says “weaving” but the footage shows a single, brief lane adjustment that any sober driver might make. When the officer’s story and the video don’t line up, that inconsistency can become the foundation of a motion to suppress. If a judge agrees the stop lacked reasonable suspicion, the evidence gathered afterward, breath test results included, may get thrown out entirely. Without that evidence, prosecutors sometimes have very little left to work with.
Most people don’t realize this defense even exists until they’ve already spoken with an officer and possibly incriminated themselves. That’s part of why we encourage clients to reach out early, before decisions get made that are hard to undo later.
DWI law in Missouri is genuinely complex, and reasonable people, including experienced judges, can disagree on where the line falls in a close case. If you’ve been charged and you’re wondering whether the stop that led to your arrest was even legal, that question deserves a serious look before you assume the case against you is solid. Give us a call and let’s talk through what actually happened that night.