It's definitely not. For example, police in Illinois have warrantless access to ipass scans.

https://www.documentcloud.org/documents/20645486-re_-externa...

  HB 4006 nullifies the entire purpose of obtaining Tollway information in an active investigation by requiring promptnotification to the subject of a search warrant and potential criminal actor. This information can be incredibly usefulin a multitude of criminal investigations, including homicides, kidnappings, and interstate trafficking of contraband.With this provision, law enforcement would not proceed with seeking a search warrant if it could jeopardize the abilityto apprehend the suspect, result in the destruction of evidence, or even worse result in harm to a victim.

  Additionally, the proposed bill forecloses the possibility of obtaining information about a person traveling through aTollway pursuant to a subpoena, including license plate information or photographs of the driver, where a knownsuspect may not be identified but the route of travel could be useful to generate leads. A warrant is not required toobtain this information. Placing such a requirement that creates greater protections beyond those required under theFourth Amendment creates an unnecessary limitation on law enforcement's ability to investigate crime. The currentrequirement to obtain a subpoena is sufficient to ensure that law enforcement has a documented investigative purposeand criminal predicate tied to Tollway information.

  Some case law background explaining why a warrant is not required for this type of Tollway information:

  "This court has not previously addressed in a published opinion the question of whether an individual has areasonable expectation of privacy in his license plate. In two unpublished decisions, however, this court has agreedwith the other circuits that have decided this issue by holding that no such privacy interest exists. The reasoning ofthese opinions, as well as that of the Supreme Court in related cases, leads us to agree that a motorist has noreasonable expectation of privacy in the information contained on his license plate under the Fourth Amendment.No argument can be made that a motorist seeks to keep the information on his license plate private. The very purposeof a license plate number, like that of a Vehicle Identification Number, is to provide identifying information to lawenforcement officials and others."