Introduction: The Responsible Decision That Led to an Arrest
Picture this. You have been drinking at a friend’s house in Scottsdale or a bar in downtown Phoenix. You know you should not drive. You make what feels like the responsible call — you get in your car, recline the seat, and sleep it off. An hour later, an officer knocks on your window. The next thing you know, you are being arrested for DUI.
Is that legal? Can Arizona police charge you with DUI for sitting or sleeping in a parked car?
The answer is yes — under the right circumstances. But it is not the whole story. Arizona courts have also clearly recognized that an intoxicated person can lawfully use a vehicle as shelter without committing a DUI — and understanding exactly where that line falls can make all the difference in your case.
Arizona DUI Law: It Is Not Just About Driving
Most people assume that a DUI requires driving. If the car is not moving, they reason, there is no DUI. In Arizona, that assumption is dangerously wrong.
Under Arizona Revised Statutes § 28-1381, a person can be charged with DUI not only for driving while impaired but also for being in actual physical control of a vehicle while under the influence of alcohol or drugs. The law does not require the car to be moving. It does not require the engine to be running. It does not even require the keys to be in the ignition. What it requires is that you were in actual physical control of the vehicle — a concept that Arizona courts have spent decades defining.
This means an officer can arrest you even if your vehicle is completely stationary, parked legally, and not going anywhere. The question is not whether you were driving. The question is whether you were in actual physical control.
What “Actual Physical Control” Means in Arizona
Arizona’s DUI statute does not precisely define actual physical control. Instead, the Arizona Supreme Court established a framework for evaluating it in State v. Zaragoza (2009), directing courts and juries to apply a totality of the circumstances analysis. No single factor is automatically determinative. The analysis is about the full picture — was this person in a position to exercise control over the vehicle and potentially set it in motion?
Factors Arizona courts and juries weigh include:
Where the keys were located. Keys in the ignition — even with the engine off — are the single strongest indicator of actual physical control. The ability to start and move the vehicle is immediately available. Keys in a pocket, purse, or on the back seat floor is more ambiguous. Keys removed entirely from the vehicle’s reach point away from actual physical control.
Which seat the person occupied. A person in the driver’s seat is in a substantially more legally vulnerable position than someone in the passenger seat or the back seat. Courts reason that someone who has moved to the back seat has taken a deliberate step away from control of the vehicle.
Whether the engine was running. A running engine is strong evidence of actual physical control. However, a non-running engine does not eliminate the risk — courts have found actual physical control with the engine off when other factors were present. And conversely, courts have recognized that running an engine for heat or air conditioning does not automatically mean a person intended to drive.
Where the vehicle was parked. A vehicle parked on a public road, in a traffic lane, or in an area where driving is imminent creates more legal concern than a vehicle in a private parking lot, a designated rest area, or a campsite. Pulling completely off the road and parking safely is a fact that courts view more favorably.
Whether the person voluntarily pulled off the road. Evidence that someone recognized they were impaired and made a deliberate decision to stop driving — rather than being stopped by police while driving — weighs in favor of the stationary shelter defense.
Whether headlights, heat, or air conditioning were on. These details suggest the vehicle’s systems were being actively used, which points toward actual control of the vehicle.
Time of day and weather conditions. A person parked at 3 a.m. outside a bar with an open container presents a different factual picture than someone parked in a campsite at midday.
Whether the person was awake or asleep. Someone asleep in the back seat has taken themselves further from immediate control of the vehicle than someone awake in the driver’s seat.
Any explanation the driver provided. What a person tells officers about why they are in the vehicle, where they came from, and what they intended to do can cut both ways — supporting or undermining the defense.
The Stationary Shelter Defense: Arizona’s Formal Legal Protection
This is the most important legal concept on this page — and the one most people facing this charge have never heard of.
Arizona courts have formally recognized what is called the stationary shelter defense: a legal doctrine that clearly distinguishes between an intoxicated person who is genuinely using a vehicle as a place to stay and a person who poses a present or imminent threat to public safety through control of the vehicle.
The Arizona Supreme Court established this principle in State v. Love (1995), holding directly that:
“It is reasonable to allow a driver, when he believes his driving is impaired, to pull completely off the highway, turn the key off and sleep until he is sober, without fear of being arrested for being in control.”
This is not a loophole or a technicality. It is a deliberate policy choice by Arizona’s highest court recognizing that the law should not punish responsible behavior. A person who recognizes they are too impaired to drive and takes steps to remove themselves from the driving situation is doing exactly what the law wants them to do. Treating that person identically to someone actively driving drunk would discourage the very behavior the public safety system depends on.
The stationary shelter principle was reaffirmed in State v. Tarr (Arizona Court of Appeals, 2014) — a case that provides a valuable and detailed window into how Arizona courts actually apply this doctrine.
State v. Tarr: What Actually Happened
Kenneth Tarr was found by Phoenix police officers in the driver’s seat of a parked car with the engine running and a BAC of 0.224% — nearly three times the legal limit. He testified that he had slept in the car after a dispute with his girlfriend and had started the engine for heat. He was charged with four counts of aggravated DUI based on driving and actual physical control while impaired.
At trial, Tarr requested a jury instruction telling jurors they should consider whether he was merely using the vehicle as stationary shelter rather than exercising actual physical control. The Court of Appeals affirmed his conviction — based in part on evidence that the vehicle had been moved — but critically confirmed that the stationary shelter defense is valid Arizona law. The court agreed that Tarr’s requested instruction was a correct statement of the law.
The takeaway for anyone facing this charge in Arizona is clear: the stationary shelter doctrine is firmly embedded in Arizona DUI law. Whether a jury applies it in your favor depends heavily on the specific facts of your situation and how those facts are presented.
The Central Question: Were You a Threat to the Public?
Under both State v. Love and State v. Zaragoza, the core inquiry for the jury is not simply whether you could have driven the vehicle. It is whether you actually posed a threat to the public by the exercise of present or imminent control over the vehicle while impaired.
This framing matters enormously. It shifts the analysis from a mechanical question about physical proximity to keys and controls toward a substantive question about public safety. A person who pulled safely off the road, turned off the engine, moved to the back seat, removed the keys from the ignition, and fell asleep presents a fundamentally different answer to that question than a person found in the driver’s seat with the engine running in a travel lane.
If you were not a threat to the public — if you took deliberate steps to remove yourself from a position of control — the stationary shelter defense gives a jury the legal basis to find in your favor even if your BAC was well above the legal limit.
A Critical Warning: The Prior Driving Issue
The stationary shelter defense protects people who are found in a legally defensible parked position. It does not protect against evidence of what happened before the car was parked.
Arizona courts have held that even if you are found in a position that supports a stationary shelter defense, evidence that you drove to that location while already intoxicated can independently support a DUI conviction based on the driving itself — separate from any actual physical control analysis.
This means that how you got to your parked location matters as much as how you were positioned when officers arrived. If witnesses observed you driving erratically before parking, if surveillance footage captures you driving to the location, or if other evidence establishes that you drove while impaired before stopping, your attorney needs to know that immediately. It fundamentally affects the defense strategy.
This is also one of the most important reasons not to make statements to officers before speaking with an attorney. A statement like “I drove here an hour ago and then realized I shouldn’t drive anymore” — intended to support a stationary shelter narrative — simultaneously establishes that you drove while impaired. What you say in those first moments matters.
Practical Steps That Reduce Your Legal Risk
If you find yourself in a situation where you have been drinking and cannot arrange a safe ride, these steps meaningfully reduce your legal exposure while also being the genuinely responsible choice.
Move to the back seat. This is the single most important step. Removing yourself from the driver’s seat signals clearly that you are not in a position to operate the vehicle and substantially strengthens a stationary shelter argument.
Remove the keys from the ignition. Place the keys somewhere that is not the ignition — in your bag, in your coat pocket, or on the back seat floor. Removing the keys from the ignition eliminates the most powerful single indicator of actual physical control.
Turn off the engine. Even if you want climate control, a running engine is a significant factor that weighs against you. If you need warmth, use blankets. The legal risk of a running engine outweighs the comfort.
Park in an appropriate location. A rest area, a campsite, a private parking lot with permission, or any location where you are clearly not in traffic is substantially better than a public street or a travel lane. Pulling completely off the road is specifically noted in State v. Love as behavior that supports the stationary shelter defense.
Do not tell officers you are waiting to drive later. Stating that you intend to drive once you feel better establishes present intent to operate the vehicle — which is exactly what supports an actual physical control finding. If you need to say anything, you are allowed to say nothing beyond providing identification.
Invoke your right to remain silent and ask for an attorney. You have the constitutional right not to answer questions. Politely but clearly stating “I would like to speak with an attorney before answering any questions” is almost always in your best interest.
None of these steps guarantee you will not be charged. But they meaningfully strengthen a stationary shelter defense if charges are filed, and they give an experienced defense attorney substantially more to work with.
DUI on Private Property: Does Location Matter?
A common follow-up question is whether Arizona’s DUI laws apply on private property — your own driveway, a private parking lot, or another non-public location. The answer is yes. Arizona’s DUI statute applies statewide and is not limited to public roads. Officers can and do make DUI arrests on private property, and the actual physical control analysis applies in exactly the same way regardless of whether the vehicle is on public or private land.
Being on private property may be a factor your attorney argues as part of the overall circumstances — particularly with respect to whether you posed a threat to the public — but it is not a complete defense on its own.
How These Cases Are Defended
Actual physical control DUI cases are among the more defensible DUI scenarios in Arizona precisely because the analysis is fact-intensive and requires the prosecution to prove something more nuanced than simply that you were driving. An experienced DUI defense attorney attacks these charges on multiple fronts simultaneously.
Raising the stationary shelter defense directly. The State v. Love and State v. Tarr framework gives defense attorneys a recognized legal doctrine to present to juries. How the instruction is framed, how the closing argument is structured, and how the specific facts are contextualized within that framework can determine the outcome.
Challenging the actual physical control factors. Each factor the prosecution uses to establish actual physical control is contestable. Key location, seat position, engine status, and the specific parking circumstances are all subject to factual challenge supported by evidence.
Challenging the chemical testing. Even in parked DUI cases, the prosecution must prove impairment through chemical testing — and that testing is subject to the same challenges available in any DUI case. Breath test calibration and maintenance, blood test chain of custody, and proper administration of field sobriety tests are all potentially fertile areas for defense challenges.
Challenging the initial contact. Officers must have a lawful basis for approaching and detaining a person even in a parked vehicle. If the initial contact was not legally justified, evidence gathered as a result may be suppressible.
Addressing the prior driving issue proactively. If evidence of prior driving while impaired exists, an experienced attorney addresses it head-on rather than hoping the prosecution does not raise it. Building a defense strategy that accounts for all the evidence — not just the evidence favorable to the defense — is essential to achieving the best possible outcome.
Frequently Asked Questions
Does the engine have to be off for the stationary shelter defense to work?
Not automatically. A running engine is a factor that weighs against you but it is not an automatic disqualifier. In State v. Tarr, the defendant’s engine was running for heat and the Court of Appeals still confirmed that the stationary shelter defense was a valid legal argument for the jury to consider. The court looks at all circumstances together — seat position, key location, where the vehicle was parked, and the full context of why the engine was running. A running engine for climate control is a different factual situation than a running engine with the driver in the driver’s seat in a traffic lane at 2 a.m.
Does it matter which seat I was in when officers found me?
Yes — significantly. Being in the driver’s seat with keys accessible makes it easier for a jury to conclude you could take control of the vehicle at any moment. Being asleep in the back seat with keys away from the ignition is a much stronger factual basis for a stationary shelter argument. The deliberate act of moving from the driver’s seat to the back seat — particularly if done before falling asleep — signals that you removed yourself from a position of control and is exactly the type of responsible behavior that State v. Love was designed to protect.
Can the prosecution use evidence that I drove to my location while drunk?
Yes — and this is one of the most important warnings on this page. Even if you are found in a perfectly parked position that supports a stationary shelter defense, Arizona courts have held that evidence of prior impaired driving to reach that location can independently support a DUI conviction based on the driving itself. This is why what you say to officers in those first moments matters enormously. Invoking your right to remain silent and asking for an attorney before answering questions is not just a legal right — it is a practical necessity in this situation.
Is the stationary shelter defense available for aggravated DUI charges?
Yes. The actual physical control element applies to both standard and aggravated DUI charges under Arizona law. In State v. Tarr, the charges were aggravated DUI — four counts — and the stationary shelter defense was still a valid argument for the jury to consider. The felony nature of the charge does not eliminate the defense. What it does is raise the stakes, which makes the quality and experience of the attorney presenting the defense even more consequential.
What if I was in a private driveway or parking lot — does that change my case?
It can be a relevant factor but it is not a complete defense. Arizona’s DUI statute applies on private property, and officers can arrest you for DUI in your own driveway. However, the private location may support the argument that you posed no threat to the public — which is the central question under the stationary shelter analysis. Whether you were on a public road versus a private property is one of the circumstances the jury considers as part of the totality of factors. It should be raised by your attorney but should not be relied upon as a standalone defense.
If I was sleeping and someone called 911 for a wellness check, can I still be charged?
Yes. A wellness check or third-party call is one of the most common ways parked DUI encounters begin. When officers arrive and find an intoxicated person in a vehicle, they conduct the same actual physical control analysis regardless of why they were called. The circumstances of the contact — wellness check versus observed driving — may be relevant to your defense in some respects, but it does not change the legal framework that applies once officers are on scene. Taking the precautionary steps described in this article — back seat, keys away from ignition, engine off, safe location — remains important regardless of whether you expect any police contact.
How Schill Law Group Defends Parked and Sleeping DUI Cases in Arizona
A DUI charge arising from a parked or stationary vehicle is not a straightforward case — and that distinction works in your favor. The stationary shelter defense, the actual physical control analysis, and the totality of circumstances framework all create genuine defense opportunities that an experienced attorney can pursue effectively.
At Schill Law Group, we defend DUI charges throughout Arizona including cases where actual physical control — rather than observed driving — is the basis for the charge. We know State v. Love. We know State v. Zaragoza. We know State v. Tarr. And we know how to apply the legal framework those cases established to the specific facts of your case in a way that gives you the strongest possible defense.
Our approach starts with a thorough review of every piece of available evidence — the officer’s body camera and dash camera footage, the police report, the chemical testing records, the specific location and circumstances of the encounter, and the full timeline of events leading up to the arrest. We identify every viable defense argument, give you an honest assessment of the strength of each, and develop a strategy tailored to your specific situation.
We do not give clients false optimism. We give them the truth about where they stand and the most effective legal representation available to improve that position. If the stationary shelter defense applies to your facts, we raise it effectively. If other challenges to the testing or the contact are available, we pursue them simultaneously. And if the prosecution has evidence of prior driving that needs to be addressed, we address it as part of a comprehensive defense strategy rather than hoping it does not come up.
If you or someone you care about has been charged with DUI in Arizona — whether arising from a traffic stop, a parked vehicle encounter, or any other circumstance — contact Schill Law Group today for a confidential consultation. There is no obligation and no cost for the initial meeting.
