When Can Police Stop a Driver for Suspected Cell Phone Use?

A police officer cannot lawfully stop a vehicle based merely on a hunch that the driver might be violating a traffic law.

A traffic stop is a seizure under the Fourth Amendment. To justify the stop, police generally must have a particularized and objective basis—reasonable suspicion—to believe that the driver committed a traffic violation or other offense.

That requirement can become particularly important when an officer observes conduct that may be completely lawful.

In United States v. Paniagua-Garcia, 813 F.3d 1013 (7th Cir. 2016), police stopped a driver because an officer believed he was texting while driving. The officer saw the driver holding a cellphone and looking toward it, but he could not actually determine that the driver was texting rather than using the phone in a lawful manner.

The traffic stop ultimately resulted in the discovery of a substantial quantity of heroin.

But evidence discovered after a traffic stop cannot retroactively create reasonable suspicion that did not exist when the officer made the stop.

The Seventh Circuit concluded that the officer lacked reasonable suspicion for the traffic stop.

Federal criminal defense attorney Michael J. Petro has more than 35 years of experience representing individuals in federal criminal cases involving illegal traffic stops, searches and seizures, drug offenses, and motions to suppress evidence.

A Traffic Stop Is a Fourth Amendment Seizure

When police activate their emergency lights and require a motorist to pull over, the government has seized that person for purposes of the Fourth Amendment.

That means the stop must be legally justified.

An officer does not necessarily need probable cause to initiate an ordinary investigatory traffic stop. Reasonable suspicion can be sufficient.

But reasonable suspicion requires more than speculation.

The officer must be able to identify objective facts supporting a reasonable belief that a violation occurred.

What Is Reasonable Suspicion for a Traffic Stop?

Reasonable suspicion is a lower standard than probable cause, but it is still a meaningful constitutional requirement.

Courts examine the totality of the circumstances.

An officer can draw reasonable inferences from training and experience, but simply observing something that could be illegal does not automatically establish reasonable suspicion.

That distinction was central to Paniagua-Garcia.

United States v. Paniagua-Garcia

In Paniagua-Garcia, an Indiana police officer observed a driver holding a cellphone.

The officer believed the driver was texting.

At the time, Indiana law prohibited certain forms of texting while operating a motor vehicle.

But holding or using a cellphone was not itself necessarily illegal.

The legal question was therefore not:

Was the driver using a cellphone?

The question was:

Did the officer have an objectively reasonable basis to believe the driver was using the phone in the particular manner prohibited by law?

The Seventh Circuit concluded that he did not.

Cell Phone Use Does Not Necessarily Mean Texting

A driver holding a cellphone might be doing many different things.

Depending upon the law applicable at the time, the driver could be:

• Looking at a telephone number
• Using navigation
• Checking the time
• Making a permitted call
• Looking at a notification
• Adjusting a phone function
• Moving the device
• Engaging in some other lawful activity

The officer must distinguish between what the law actually prohibits and conduct that merely resembles prohibited conduct.

That does not mean police must know with certainty that a violation occurred.

Reasonable suspicion does not require certainty.

But there must be enough objective information to move the officer’s conclusion beyond a mere possibility.

What Did the Officer Actually See?

This is often one of the most important questions in challenging a traffic stop.

Consider the difference between:

“I saw the driver using a phone.”

and:

“I clearly observed the driver repeatedly typing into the phone while operating the vehicle.”

Those are substantially different observations.

A suppression motion should identify precisely what the officer claims to have observed.

Important questions may include:

• Where was the officer positioned?
• How far away was the officer?
• Was it daytime or nighttime?
• How long did the officer observe the driver?
• Could the officer see the phone’s screen?
• Could the officer see the driver’s fingers?
• Was the vehicle moving?
• What exactly did the driver do?
• Did the officer record the observation?
• Does dashcam or body-camera video support the officer’s account?

The constitutional analysis should be based on what the officer actually knew before the stop occurred.

Evidence Found Later Cannot Justify an Illegal Stop

Suppose police stop a vehicle without reasonable suspicion and subsequently discover:

• Drugs
• A firearm
• Cash
• Contraband
• Evidence of fraud
• Evidence of another crime

The discovery of that evidence does not travel backward in time and create reasonable suspicion for the original traffic stop.

The government must justify the seizure based upon the facts known to the officer at the moment the stop was initiated.

That was particularly significant in Paniagua-Garcia because the stop ultimately resulted in the discovery of serious evidence.

The constitutional question nevertheless remained whether the officer had lawful grounds to stop the vehicle in the first place.

An Illegal Traffic Stop Can Lead to Suppression of Evidence

When a traffic stop violates the Fourth Amendment, the defense can seek suppression of evidence obtained as a result of the unlawful seizure.

This can include evidence discovered during a subsequent vehicle search.

For example, an officer may stop a vehicle and then:

1. Question the driver.
2. Order occupants from the vehicle.
3. Call a drug-detection dog.
4. Obtain alleged consent.
5. Search the vehicle.
6. Discover drugs or firearms.

Before analyzing the later search, defense counsel should ask:

Was the initial traffic stop lawful?

If the answer is no, evidence obtained because of the illegal stop may potentially be suppressed, subject to any applicable exception to the exclusionary rule.

The Government Cannot Use Evidence Found Later to Cure the Stop

Suppression cases sometimes involve very serious evidence.

That can distract attention from the actual constitutional issue.

The Fourth Amendment analysis does not become:

“The police found drugs, so the stop must have been justified.”

The analysis begins before the drugs were found.

What facts did the officer possess when the officer seized the driver?

If those facts did not establish reasonable suspicion, later discovery of contraband does not itself cure the original constitutional defect.

Mistakes of Fact Can Sometimes Support a Traffic Stop

Not every police mistake makes a traffic stop unconstitutional.

The Fourth Amendment requires reasonableness, not perfection.

An officer can sometimes make an objectively reasonable mistake of fact.

For example, an officer may reasonably perceive conduct as a traffic violation and later discover that an important factual assumption was incorrect.

The critical question is whether the mistake was objectively reasonable under the circumstances.

What About a Police Officer’s Mistake About the Law?

Mistakes of law require a separate analysis.

In Heien v. North Carolina, 574 U.S. 54 (2014), the Supreme Court held that an objectively reasonable mistake of law can support reasonable suspicion for a traffic stop.

The officer in Heien stopped a vehicle because one of its brake lights was not functioning.

The relevant North Carolina law was subsequently interpreted to require only one working brake light.

The officer therefore had been mistaken about the law.

Nevertheless, the Supreme Court held that the mistake was objectively reasonable because of the genuine ambiguity in the statutory provisions.

Heien Does Not Excuse Every Police Mistake

Heien does not give police unlimited authority to misunderstand traffic laws.

The mistake must be objectively reasonable.

An officer cannot gain a Fourth Amendment advantage merely by failing to understand a clear traffic statute.

That distinction can become critical in a motion to suppress.

Mistake of Fact Versus Mistake of Law

Defense counsel should determine exactly what mistake the government claims occurred.

A mistake of fact might be:

The officer reasonably believed the driver was typing a text message, but the driver was actually performing another function on the phone.

A mistake of law might be:

The officer correctly observed what the driver was doing but mistakenly believed the traffic statute prohibited that conduct.

Those present different legal questions.

Either type of mistake may potentially be consistent with the Fourth Amendment, but only when the mistake is objectively reasonable.

The Exact Traffic Statute Matters

Traffic-stop litigation frequently turns on the actual language of the statute.

It is not enough for an officer to testify generally:

“I thought what he was doing was illegal.”

The defense should identify:

• The exact statute allegedly violated
• The statutory language in effect on the date of the stop
• What conduct the statute prohibited
• Any statutory exceptions
• Appellate decisions interpreting the statute
• Whether the officer’s observations actually fit the statutory elements

This analysis can reveal that the conduct observed by police was not illegal at all.

Cell Phone Laws Have Changed

Cellphone and distracted-driving statutes have changed significantly over time.

Some laws prohibit handheld use generally.

Others prohibit particular activities.

Some distinguish between:

• Texting
• Voice calls
• Navigation
• Emergency communications
• Hands-free operation
• Stopped vehicles

That makes it important to analyze the law in effect at the time and place of the traffic stop rather than applying today’s cellphone law to an older case.

Paniagua-Garcia must be understood in the context of the Indiana statute applicable when that traffic stop occurred.

Dashcam Video Can Be Critical

Modern traffic-stop cases frequently include video evidence.

Dashcam footage may establish:

• The officer’s location
• Lighting conditions
• Distance from the suspect vehicle
• Traffic conditions
• How long the officer observed the vehicle
• Whether the alleged violation is visible
• Statements the officer made immediately after the stop

The video can sometimes confirm the officer’s testimony.

In other cases, it can contradict it.

That is why defense counsel should obtain and review the original video rather than relying exclusively on the police report.

Body-Camera Evidence Can Also Matter

Body-camera footage generally begins after the officer has initiated the stop, so it may not show the alleged traffic violation itself.

It can nevertheless provide important evidence.

For example, the officer may tell the driver:

“I stopped you because I saw you texting.”

Or the officer may describe the observation differently from the later police report.

Those statements can become important when testing the government’s explanation for the stop.

Police Reports Should Be Compared With Testimony

A suppression hearing gives defense counsel an opportunity to test the officer’s account.

The officer’s:

• Police report
• Dashcam recording
• Body-camera recording
• Citation
• Dispatch communications
• Deposition or prior testimony
• Suppression-hearing testimony

should be compared carefully.

Differences can matter.

An officer who initially wrote only that the driver was “using a cellphone” may have difficulty later claiming that the officer clearly saw the driver composing a text message.

Reasonable Suspicion Must Exist Before the Stop

The timing of the officer’s knowledge is critical.

Facts learned after the seizure ordinarily cannot establish reasonable suspicion for a seizure that has already occurred.

Defense counsel should therefore construct a timeline:

What did the officer observe first?

What did the officer know when the emergency lights were activated?

When did the vehicle stop?

What information was learned afterward?

Separating pre-stop facts from post-stop facts can expose an otherwise hidden weakness in the government’s justification.

Pretext Does Not Eliminate the Reasonable-Suspicion Requirement

Police sometimes use traffic enforcement as an opportunity to investigate suspected criminal activity.

An officer may suspect that a vehicle contains drugs but lack reasonable suspicion of a drug offense.

If the officer observes an actual traffic violation, that violation can provide an objective basis for a stop.

But if the alleged traffic violation did not occur, the government may need to establish another objectively reasonable basis for the seizure.

An investigative objective does not itself supply reasonable suspicion.

A Lawful Stop Can Become Unlawfully Prolonged

Even when the initial traffic stop is lawful, the Fourth Amendment analysis does not necessarily end.

Police generally cannot prolong a completed traffic investigation simply to investigate unrelated criminal activity without additional legal justification.

Thus, a suppression motion can involve two separate questions:

Was the stop lawful at its inception?

and

Was the stop unlawfully extended after its legitimate traffic purpose should have ended?

Both questions can affect the admissibility of subsequently discovered evidence.

What Should Defense Counsel Examine After a Traffic Stop?

When a federal prosecution begins with a traffic stop, the legality of that stop should be examined independently from the seriousness of the charges that followed.

Important questions include:

• What precise violation did the officer claim?
• What did the officer actually observe?
• How long did the officer observe it?
• What did the applicable statute prohibit?
• Was the officer mistaken about the facts?
• Was the officer mistaken about the law?
• If mistaken, was that mistake objectively reasonable?
• Is there dashcam video?
• Is there body-camera video?
• Do the recordings support the police report?
• When was contraband discovered?
• Was consent obtained after the stop?
• Was the stop unlawfully prolonged?
• Was a drug dog used?
• Did the government develop probable cause only after the initial seizure?

Each stage should be analyzed separately.

Why Paniagua-Garcia Remains Important

The continuing value of Paniagua-Garcia is not that police can never stop someone suspected of texting while driving.

They can when the facts and applicable law provide reasonable suspicion.

The broader lesson is this:

Police must have objective facts supporting a reasonable inference that the conduct they observed actually violated the law.

The possibility that innocent conduct might represent illegal activity is not automatically enough.

And serious evidence discovered after the stop cannot retroactively supply reasonable suspicion that was missing beforehand.

Suppression Can Change the Entire Criminal Case

When an illegal traffic stop leads directly to discovery of the government’s principal evidence, a successful motion to suppress can fundamentally change the prosecution.

If critical drugs, firearms, statements, or other evidence are excluded, the government may have difficulty proving the charges.

That is why the legality of the initial traffic stop should never be dismissed as a minor issue merely because officers later discovered serious evidence.

The Fourth Amendment inquiry begins with the seizure.

The Lesson From United States v. Paniagua-Garcia

Paniagua-Garcia illustrates a basic Fourth Amendment principle.

Police do not need certainty before stopping a vehicle.

They do need reasonable suspicion.

An officer who observes conduct that might be unlawful must have sufficient objective facts to reasonably distinguish suspected illegal conduct from innocent behavior.

And the government’s discovery of incriminating evidence after the stop does not change what the officer knew when the seizure began.

That principle can determine whether evidence obtained during a traffic stop is admissible in federal court.

Experienced Federal Search and Seizure Attorney Michael J. Petro

Michael J. Petro has more than 35 years of criminal defense experience representing individuals facing serious federal criminal charges.

Traffic stops frequently become the starting point for federal drug, firearm, and other criminal prosecutions. A seemingly routine traffic violation can lead to questioning, a vehicle search, seizure of evidence, arrest, and ultimately a federal indictment.

Defense counsel should examine the legality of the stop from its very beginning.

If police lacked reasonable suspicion, misunderstood the traffic law, relied on an unreasonable factual assumption, or unlawfully extended the detention, the defense may have grounds to seek suppression of evidence obtained as a result of the seizure.

If you are facing federal charges arising from a traffic stop, vehicle search, or seizure of evidence, contact federal criminal defense attorney Michael J. Petro to discuss whether the government’s evidence can be challenged.