This question comes out of reading this New York Times article (quoted below), about a bill that would allow officers to use a "textalyzer" to digitally search phones for evidence that the phones had been handled recently:

The technology could determine whether a driver had used the phone to text, email or do anything else that is forbidden under New York’s hands-free driving laws, which prohibit drivers from holding phones to their ear. Failure to hand over a phone could lead to the suspension of a driver’s license, similar to the consequences for refusing a Breathalyzer.

The intention is behavior change:

“We need something on the books where people’s behavior can change,” said [Félix W. Ortiz, a Democratic assemblyman who was a sponsor of the bipartisan Textalyzer bill], who pushed for the state’s 2001 ban on hand-held devices by drivers. If the Textalyzer bill becomes law, he said, “people are going to be more afraid to put their hands on the cellphone.”

The US Supreme Court has unanimously ruled that when somebody is arrested, their phone can't be searched without a warrant.

But the bill’s authors say they have based the Textalyzer concept on the same “implied consent” legal theory that allows the police to use the Breathalyzer: When drivers obtain a license, they are consenting in advance to a Breathalyzer, or else they will risk the suspension of their license.

(Emphasis added.)

The analogy to the Breathalyzer is based on comparability of dangers, too:

Deborah Hersman, the president of the nonprofit National Safety Council and a former chairwoman of the National Transportation Safety Board, ... said the Textalyzer-Breathalyzer comparison was apt because looking at and using a phone can be as dangerous as driving drunk. “Why are we making a distinction between a substance you consume and one that consumes you?”

How far does this "implied consent" legal theory go? Can it be extended to mean that drivers' license applicants give "implied consent" to have their cars, homes, or body cavities searched in detail, or give "implied consent" to physical control by police (to enforce any failures to comply with an instruction), etc., if police request that power and find a suitably sympathetic audience in the General Assembly?

It's an old argument that increasing police search powers increases safety, because it allows the police to search out and stamp out whatever behavior creates the danger to others. Where's the line, if any, which limits the extent of how far that can go? What do people really consent to when applying for a driver's license?

Can "implied consent" be retroactive, such that if I have a New York driver's license today, that means I've given "implied consent" to whatever permissions the General Assembly grants police a couple years after I've gotten that license? If not, does a license renewal establish that "consent?" There is some precedent in that having gotten a NY license a few years ago does indicate consent to be bound by traffic laws including updates and changes that occur during the period of license validity. Is "implied consent" to searches one of the topics covered by that?

This is tagged for New York, but as the article notes:

If it were to pass in New York,... it could well spread in the same way that the hands-free rules did after New York adopted them.

So feel free to answer for other jurisdictions, if they are a better fit for your expertise, and note that in your answer.

  • Are you familiar with Birchfield v. North Dakota
    – user3851
    Apr 28, 2016 at 16:18
  • @Dawn nope, thanks for the link. It looks like even SCOTUS thinks this is basically a good question / worthy of their time, but the case was argued just last week so we'll have to wait a bit on their answer.
    – WBT
    Apr 28, 2016 at 19:03
  • The briefs are a great summary of the state of implied consent law in the context of driver licencing and traffic stops. The texting hypothetical even came up at oral argument. Page 36: "if people find that texting while driving is becoming an increasing problem, and so when you get a license, [you] give implied consent for the officer to look at the [texts] on your cell phone to make sure, [...], a minute ago you were texting somebody while driving? [Would] that be acceptable under your rationale?"
    – user3851
    Apr 28, 2016 at 19:22
  • Not-a-law-student, but if it's something external (like a blinking LED or a message on the lock screen) does that count as searching?
    – Nate D
    Nov 15, 2017 at 16:10
  • @NateD I think that would depend on if the phone was visible and the thing observed was in plain view during a normal traffic stop etc.
    – WBT
    Nov 15, 2017 at 17:31

2 Answers 2


Breathalyzer tests are distinct from blood tests because the former does not "implicat[e] significant privacy concerns" (see Birchfeld v. ND). A cell phone is like a blood test, because it implicates significant privacy concerns, especially the level of electro-snooping that would be required to determine if someone had recently committed a phone-use offense. As the court held,

Because the impact of breath tests on privacy is slight, and the need for BAC testing is great, the Fourth Amendment permits warrantless breath tests incident to arrests for drunk driving.

A breath test might (but also might not) also satisfy the exigent-circumstances exception (waiting some number of hours for a warrant can easily result in the destruction of evidence), but a cell phone case could not give rise to such an exception.

It should perhaps be noted that the "implied consent" laws are misnamed, because consent is not the issue. The 4th Amendment ban is on unreasonable searches, not unconsented searches. If you actually consent, it is reasonable for the police to search. I am not aware of any ruling to the effect that "because the defendant consented, the search is valid". In the context of breathalyzer law and case-law, an essential component of what makes the search reasonable is that it is incident to an arrest. With or without consent, or an implied consent law,

Having assessed the effect of BAC tests on privacy interests and the need for such tests, we conclude that the Fourth Amendment permits warrantless breath tests incident to arrests for drunk driving.

Extending "implied consent" to cause-unrelated searches of cars, homes, or body cavities might not pass strict scrutiny. The state has a legitimate interest in public safety which justifies some minimal intrusion, but adding a provision that "when you drive, you give implied consent to searches of everything" is not narrowly tailored. But since driving is a privilege and not a right, the state has much more leeway to give you an ultimatum: if you don't cooperate with the search, you can lose your license. On the other hand, SCOTUS has not actually approved of this slogan about driving being a privilege.

Something noteworthy from Birchfield is that the court also disapproves of blood tests because a less invasive method of achieving the result is available, and they grant that "Imposition of a warrant requirement for every BAC test would likely swamp courts, given the enormous number of drunk-driving arrests, with little corresponding benefit". There being no less-invasive alternative means of realizing the legitimate state interest in stopping distracted driving, I actually expect that when this comes to pass and the matter ends up at SCOTUS, there will be another important change in search law (but "implied consent" will still be irrelevant).

  • 1
    "An essential component of what makes the search reasonable is that it is incident to an arrest." Not necessarily. There are a LOT of searches (and seizures of property, even when in violation of explicit state law, which should also theoretically be subject to 4th Amendment Protection) not associated with an arrest. Alcohol etc also get metabolized out of the blood in a time-scale of hours, so that doesn't seem to be the distinction.
    – WBT
    Mar 16, 2018 at 12:12

Implied consent does NOT rest upon the acquiring of a license. (Otherwise, someone who never had a license would be immune.) Rather, it is triggered by driving in the state.

According to the Supreme Court case Birchfield v. North Dakota, criminal penalties for refusing breath tests (but not blood tests) are OK. However, one of the considerations is that evidence might be destroyed (by normal metabolism) while the warrant is being sought. This is less likely to happen when dealing with a cell phone.

I don't know exactly where the line is when it comes to implied consent, but the Court assures us that there IS a line somewhere, and blood tests are on the wrong side of it:

It is another matter, however, for a State not only to insist upon an intrusive blood test, but also to impose criminal penalties on the refusal to submit to such a test. There must be a limit to the consequences to which motor­ists may be deemed to have consented by virtue of a deci­sion to drive on public roads

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