Effective March 15, 2026, Wisconsin law enforcement can request a roadside saliva (oral-fluid) drug screen before arrest when the officer has the statutory basis required by § 343.303. For ordinary motor-vehicle OWI stops, that means probable cause to believe the driver is violating, or has violated, Wisconsin’s OWI laws. The new authority comes from 2025 Wisconsin Act 99, enacted on March 13, 2026, published on March 14, 2026, and originally introduced as Senate Bill 678.
Headlines have framed the new test as a kind of “drug breathalyzer.” That framing is wrong, and the misunderstanding has the potential to cost Racine, Kenosha, and Walworth County drivers their licenses unnecessarily. Here is what the law actually says, what your refusal options actually are, and where the saliva result fits into a Wisconsin OWI case.
What Act 99 Actually Did, In One Sentence
For ordinary motor-vehicle OWI stops, Act 99 added the words “or oral fluids, or both” to § 343.303, the statute that already governed roadside preliminary breath tests. The new law did not amend Wisconsin’s implied-consent statute (§ 343.305), it did not amend the OWI statute itself (§ 346.63), and it did not create a new evidentiary chemical test. It gave officers a new preliminary screening tool, and that screening tool sits on the same legal footing as the existing roadside breath PBT for alcohol.
That distinction is the entire ballgame.
Where the roadside swab fits in Wisconsin law
This is a statute map, not a geographic map. The most important defense point is the statutory lane the test occupies. Act 99 lives in the preliminary-screening statute. The arresting officer still needs probable cause for arrest and still needs a separate implied-consent request for the evidentiary blood test.
Before arrest
The oral-fluid swab is requested under § 343.303. It can support probable cause, but it is not the test that proves guilt.
After arrest
The officer requests breath, blood, or urine under § 343.305. This is the implied-consent decision with the refusal-revocation risk.
At charging
The prosecutor usually charges under § 346.63. THC cases often turn on the prohibited-substance provision, not proof that the driver looked impaired.
- Ask for squad video, body camera, dispatch notes, and the officer's drug-recognition observations.
- Request device training, calibration, quality-control, and maintenance records.
- Separate the roadside refusal from any post-arrest implied-consent refusal.
- Cross-check the blood result against the roadside-screen timeline and reported last use.
Can You Refuse the Saliva Test?
Yes. And refusing the swab itself does not trigger the implied-consent license revocation that Wisconsin drivers fear, because that revocation lives in § 343.305, not § 343.303.
The § 343.303 PBT rule has always allowed drivers to decline a roadside screening device without an automatic license consequence. Act 99 carried that rule forward. Refusing the saliva swab is legally identical, on the license-track question, to refusing the roadside breath PBT for alcohol.
What refusing the swab will often do is move the encounter toward arrest. The officer is going to use whatever else he has (driving behavior, odor, observation, statements, field-sobriety performance) to establish probable cause and then request a post-arrest chemical test under § 343.305. In a drugged-driving case, that usually means blood. Refusing that implied-consent test is different from refusing the roadside swab. A first improper refusal generally carries a one-year revocation if sustained or not timely challenged, with longer revocations for drivers with prior counts and separate rules for some minor-passenger cases. (See our partner OWI site for the 10-day refusal-hearing deadline and what the hearing actually decides.)
The two refusal decisions are different decisions at different stages of the stop. Conflating them is the single biggest mistake drivers and even some attorneys are making in the early weeks of Act 99.
The Saliva Result Itself Is Generally Not Admissible to Prove Guilt
Under § 343.303, a preliminary screening result is admissible only:
- To show the officer had probable cause for arrest,
- To show that a chemical test was properly requested, or
- To rebut a probable-cause challenge.
It is not admissible to prove impairment or guilt at trial. The state still has to prove the OWI with admissible evidence, usually the post-arrest chemical test plus officer observations and any field-sobriety evidence. Act 99 carried this rule forward to oral-fluid screening. We have not yet seen Wisconsin appellate interpretation of Act 99 specifically, but the statutory admissibility rule is direct and matches how the breath PBT has been treated for decades.
Practically: a positive saliva result will lead many officers to arrest, but the result itself is not what the prosecutor usually tries to put in front of a jury. In a drugged-driving case, the blood result is usually the state’s central chemical evidence.
Presence, Not Impairment, And Why That Matters Most for Cannabis
The Abbott SoToxa and similar oral-fluid devices detect the presence of a substance in saliva at the time of the swab. They do not measure quantity, and they do not measure impairment. They return a binary positive or negative on each panel.
For cannabis specifically, this gap matters enormously. Peer-reviewed studies put oral-fluid delta-9 THC detection at roughly 8 to 24 hours after use, well past the 3-to-4-hour typical impairment window. A driver who legally bought cannabis at a dispensary in Illinois, Michigan, or Minnesota, used it on Friday night, and is stopped on I-94 in Pleasant Prairie on Saturday morning may register positive on the saliva test without being remotely impaired at the time of the stop.
That driver, however, is in a worse position than the saliva test alone suggests. Wisconsin’s prohibited-substance OWI statute, § 346.63(1)(am), is zero-tolerance. Any detectable amount of delta-9 THC, cocaine, or other listed restricted controlled substance in the blood can support a per se OWI charge, with no need to prove actual impairment. The saliva screen can help create probable cause for the blood draw. The blood result is usually what drives the prohibited-substance count. Our Wisconsin marijuana laws and charges page covers the full prohibited-substance framework.
What the Substance Panel Actually Includes
Public reporting on Act 99 has focused on three categories: THC, opioids, and stimulants. The statute authorizes oral-fluid preliminary screening, but the actual panel run during a stop depends on the device and agency practice. The Abbott SoToxa, one roadside device used in drug-screening programs, can screen for six substance categories:
- THC (delta-9 tetrahydrocannabinol)
- Amphetamine
- Methamphetamine
- Cocaine
- Opiates (heroin and prescription opioid metabolites)
- Benzodiazepines
If your prescription anxiety medication or pain medication contains a benzodiazepine or opioid, the device can return a positive on those panels. The screening result is not an impairment determination. A valid prescription or practitioner order can be an important defense fact, but it is not a free pass if the state alleges the medication made the driver incapable of safely driving. The saliva positive can still produce an arrest.
What to Do at the Roadside, In Order
This is the sequence we walk Racine, Kenosha, and Walworth County clients through:
- Be polite, identify yourself, and stop talking. Provide license, registration, proof of insurance. You are not required to answer where you have been, what you have consumed, or what you have done in the last 24 hours. The squad-camera audio captures everything you say.
- Field sobriety tests are voluntary. Refusing them carries no automatic license consequence, though the refusal can still become part of the officer’s probable-cause narrative. Their interpretation is highly subjective and is a major source of probable cause. Many drivers, especially those who would face medical disadvantages performing them sober, choose to decline.
- The roadside saliva swab is voluntary in the same way. Refusing it does not trigger § 343.305 revocation. Refusing will move the stop toward arrest.
- Once arrested, the calculation changes. The officer reads the Informing the Accused form and requests a chemical test under § 343.305, which in a drug case usually means blood. That is the implied-consent test. Refusing it can trigger the refusal-hearing track and, for a first improper refusal, generally a one-year revocation. The decision to submit to or refuse the post-arrest chemical test is materially different from the decision to submit to or refuse the roadside swab.
- Call a defense attorney before making any further statement. Cafferty & Scheidegger answers OWI calls 24/7 at (262) 632-5000.
The Bottom Line
Act 99 is a screening-tool authorization, not a new evidentiary regime. The roadside saliva swab is voluntary on the same legal footing as the existing breath PBT. Refusing it does not, by itself, revoke your license. Refusing the post-arrest implied-consent test can. The saliva result itself does not prove guilt. In a drugged-driving case, the post-arrest chemical test is usually the central chemical evidence.
For Racine, Kenosha, and Walworth County drivers, the practical effect of Act 99 is that a marijuana possession case can now begin at the roadside instead of waiting for the search of the vehicle. Cross-border drivers returning from Illinois, Michigan, or Minnesota dispensaries are especially exposed because oral-fluid THC detection can outlast the impairment window, and Wisconsin’s blood-based prohibited-substance law remains unforgiving.
If you have been stopped, swabbed, or arrested on a saliva-test stop in any of the three counties, the first 24 hours are the highest-leverage window for preserving the evidence that defends the case: the squad video, the device calibration record, the training records of the operating officer, the chain of custody on both the swab and the blood draw. We file preservation requests the same day a case comes in.
For the full procedural breakdown of how Act 99 fits into a Wisconsin OWI case, including the FAQ-grade detail and the refusal-hearing interaction, see our partner OWI site at racineowi.com/roadside-saliva-test/.
For the Wisconsin marijuana-law context that drives most saliva-test stops in 2026, including the federal April 28, 2026 rule for FDA-approved marijuana products and state medical-marijuana-license products and the cross-border legal-purchase trap, see our Wisconsin marijuana laws page and our 2026 reference guide Is Weed Legal in Wisconsin?.
Call or text 24/7 at (262) 632-5000 for a free, confidential consultation. We have defended Wisconsin OWI and drug cases continuously since 1994.