For most of automotive history, a car remembered almost nothing.
You could drive across town, park for an hour and return home. Unless someone saw you, photographed the vehicle or recorded the trip in some other way, the car itself had little to say about where it had been.
Modern vehicles are different.
Many are computers on wheels.
They can contain navigation systems, wireless connections, event data recorders, infotainment systems and links to smartphone applications and remote services. Outside the vehicle, toll readers, parking systems and automated license-plate cameras can create still more records of a trip.
As a result, a question that once would have sounded strange has become increasingly important in criminal investigations and lawsuits:
What does the car know about where it has been?
The answer depends enormously on the vehicle and the systems involved. There is no single database inside every automobile containing a perfect history of every trip.
But a modern vehicle can create pieces of information that, when combined with other records, may help reconstruct where it traveled, when it was there and sometimes what happened along the way.
The Car Itself Is Only Part of the Story
When people talk about vehicle tracking, several very different technologies tend to get grouped together.
Some information may exist inside the vehicle.
Some may be maintained by a manufacturer or connected-service provider.
Some may come from a driver's phone.
And some may be generated by infrastructure the car passes during a trip.
Consider a drive across a metropolitan area.
The navigation system may contain a destination.
The driver's phone may generate location-related information.
A toll system may record the vehicle.
A parking garage may log an entry.
A license-plate reader may photograph the plate.
A store camera may record the car arriving.
The vehicle's own systems may contain additional information.
None of those records necessarily provides a complete account.
Together, however, they can begin to reconstruct the trip.
Your Navigation System May Remember More Than You Expect
Built-in navigation systems are an obvious potential source of location information.
Depending on the vehicle and system, navigation data may include saved addresses, recent destinations, favorite locations or route-related information.
Think about what those records can reveal.
A destination entered into a navigation system does not necessarily prove that the driver actually reached that location.
But it can establish that someone using the system searched for or selected the destination.
If other evidence shows the vehicle near that location shortly afterward, the navigation information becomes more significant.
The same principle applies in the opposite direction.
A vehicle's records may help contradict an assertion about where it traveled.
Digital evidence often becomes powerful not because one record answers every question, but because several independent records tell a consistent story.
The Phone and the Car Have Become Connected
The distinction between phone data and vehicle data has also become increasingly blurry.
Drivers routinely connect smartphones to vehicles through Bluetooth, USB connections and smartphone-integration systems.
That allows the vehicle to display contacts, make calls, play messages, access music and use navigation services.
Depending on the system and how it is configured, information associated with connected devices can sometimes remain available in the vehicle.
That possibility has attracted the attention of digital-forensics investigators.
A vehicle recovered after a crime may potentially contain useful information associated with devices that previously connected to it.
But the existence and recoverability of such information varies substantially among vehicles.
A five-year-old economy car and a new luxury vehicle may have completely different electronic systems.
Even two vehicles from the same manufacturer may behave differently depending on software, equipment and settings.
There is no universal rule that every car stores the same information.
The Car May Record What Happened During a Crash
Location information is only one category of automotive data.
Many vehicles contain event data recorders.
These systems are sometimes compared to an airplane's “black box,” although the comparison can exaggerate what they actually do.
An event data recorder generally is not designed to continuously record everything that happens during every drive.
Instead, it can preserve certain vehicle information associated with a crash or other triggering event.
Depending on the system, recorded information can concern matters such as vehicle speed, braking, accelerator position, seat-belt status and changes in velocity.
That information can become extremely important after a serious collision.
Two drivers may remember an accident differently.
Witnesses may disagree.
Skid marks may be unclear.
Video may not exist.
Electronic vehicle data can provide another source of evidence.
But, as with other digital evidence, investigators still must determine exactly what a particular system recorded and what conclusions the data actually supports.
The Supreme Court Has Already Confronted Electronic Tracking of Cars
The constitutional significance of vehicle tracking reached the Supreme Court in United States v. Jones.
Police investigating Antoine Jones installed a GPS tracking device on a vehicle and used it to monitor the vehicle's movements.
In 2012, the Supreme Court held that the government's installation of the GPS device on the vehicle and its use to obtain information constituted a Fourth Amendment search.
The case involved a tracking device physically installed by law enforcement, not data automatically generated by a modern connected car.
That distinction matters.
But Jones became an important part of the larger legal discussion about technology and location tracking.
The case demonstrated that technological surveillance of a vehicle can raise constitutional questions even though the vehicle travels on public roads.
Seeing a Car Once Is Different From Reconstructing Its Life
Imagine an officer standing beside a road.
A blue sedan drives past.
The officer sees it.
There ordinarily is nothing remarkable about that observation.
Now imagine cameras throughout a region automatically recording the same vehicle every time it passes.
One observation becomes ten.
Ten become a thousand.
Instead of knowing that the vehicle was at one intersection on Tuesday afternoon, a database may begin to reveal patterns.
Where does the vehicle spend the night?
Where does it appear each morning?
What medical offices does it visit?
What religious institutions does it visit?
What political events does it attend?
Who appears to travel with it?
Technology changes surveillance partly by changing its scale.
That is one reason modern location cases increasingly involve not merely whether something could have been observed in public, but how much information can be accumulated and searched over time.
Your License Plate Can Create a Travel Record Outside the Car
A vehicle does not need sophisticated electronics to leave a digital trail.
Its license plate can do that.
Automated license-plate readers photograph vehicles and extract plate information as cars pass cameras.
Depending on the system, a detection can be associated with the date, time and location where the vehicle was observed.
One camera observation says relatively little.
A network of cameras can say much more.
If the same plate is recorded at several locations, those observations can help reconstruct the vehicle's movements.
This is different from information stored inside the automobile.
The vehicle itself may contain no record of the camera encounter.
The record exists because infrastructure outside the car observed it.
That distinction becomes important when courts analyze how the information was obtained.
Toll Roads Can Become Part of the Timeline
Electronic toll systems create another source of travel information.
When a vehicle passes through a tolling location, the system may generate a transaction associated with the vehicle or account.
A parking structure may create similar records.
So can gated communities, automated garages and other access-control systems.
Suppose investigators are trying to determine whether a vehicle traveled from one city to another on a particular morning.
A toll transaction at 8:12 a.m. does not necessarily establish who was driving.
But it may help establish that a vehicle associated with the account passed a particular point around that time.
Combine that with a camera observation, phone records and a purchase made later in the morning, and a more complete timeline can emerge.
The Car Does Not Necessarily Identify the Driver
This is one of the most important limitations of vehicle evidence.
Evidence about a car is not automatically evidence about the person driving it.
A license-plate camera may establish that a particular vehicle passed a location.
It does not necessarily show who was behind the wheel.
Navigation history may show that someone entered a destination.
It does not necessarily establish who entered it.
A connected phone may help identify someone associated with the vehicle.
It does not necessarily establish that person was driving during every trip.
Cars are loaned to family members.
Rental cars change drivers.
Employees use company vehicles.
Friends borrow vehicles.
Multiple people may have keys.
This distinction can become critical in court.
Digital evidence can be highly precise about the location of an object while remaining uncertain about the identity of the person controlling it.
Manufacturer-Connected Services Add Another Layer
Modern cars increasingly communicate with remote systems.
Drivers can use applications to locate a parked vehicle, check charging status, lock doors, start climate controls or receive diagnostic information.
Those conveniences require communication between the vehicle and systems outside it.
That creates another category of potential records.
In some circumstances, law enforcement may seek information held by a manufacturer or service provider rather than extracting it directly from the automobile.
Exactly what information exists, how long it is retained and how it may legally be obtained depends on the particular service and circumstances.
Those details can change as manufacturers update their products and privacy practices.
The enduring legal issue is broader:
A vehicle is no longer necessarily an isolated machine.
It may be one component of a connected information system.
A Stolen Car Shows Why This Technology Can Be Useful
The same technology that raises privacy questions can have obvious investigative benefits.
Imagine a vehicle is stolen from a driveway overnight.
A neighborhood camera records it leaving.
A license-plate reader detects it several miles away.
A connected-vehicle service provides another source of information.
A toll system records the vehicle later that morning.
Each piece can help investigators locate the car and determine where it traveled.
Location technology can also help find vehicles associated with missing people, wanted suspects and emergencies.
The difficult legal questions arise because systems capable of locating a stolen vehicle may also be capable of recording the movements of millions of people who are not suspected of wrongdoing.
The technology itself does not distinguish between those situations.
Rules governing access, retention and use do.
A Search Warrant May Target the Vehicle's Electronics
When investigators lawfully obtain a vehicle during an investigation, they may seek authority to examine its electronic systems.
The process can resemble digital forensics performed on computers and phones.
Investigators may attempt to identify information relevant to a particular crime.
But the same Fourth Amendment principles that govern other searches remain important.
A search warrant ordinarily must be supported by probable cause and must particularly describe the place to be searched and the things to be seized.
Applying those principles to modern electronics can become complicated.
What exactly counts as the place being searched?
The infotainment system?
A particular electronic control unit?
Data synchronized from a phone?
Information stored remotely by a connected service?
Technology can make a seemingly simple object contain several legally distinct sources of information.
Data Can Outlast the Trip
One of the unusual characteristics of digital evidence is persistence.
A trip may last twenty minutes.
The records associated with it can remain much longer.
A person may forget the route entirely.
A computer may not.
A destination can remain in navigation history.
A transaction can remain in an account.
A photograph can remain in a database.
A parking record can remain on a server.
A phone connection can leave another record.
This means investigators sometimes can reconstruct aspects of an event long after everyone involved has forgotten the details.
The investigation begins in the present.
The computers look backward.
But Data Is Not Automatically Correct
Electronic records can appear more authoritative than they really are.
A number displayed by a computer feels precise.
Precision is not the same as accuracy.
A license plate can be misread.
A GPS position can be imprecise.
A vehicle clock can be wrong.
An account can be associated with someone who was not driving.
A database entry can be stale.
A navigation destination can have been entered but never visited.
A connected device can belong to a passenger.
Forensic interpretation therefore matters.
The question is not simply whether data exists.
The question is what the data reliably proves.
A Car Can Become a Witness Without Knowing It
For decades, investigators reconstructed vehicle movements primarily through people and physical evidence.
A witness remembered seeing the car.
A gas-station employee recognized the driver.
A paper receipt showed a purchase.
Tire tracks suggested where the vehicle traveled.
Those forms of evidence still matter.
But modern investigations can add an entirely new category.
The car's electronics.
The driver's electronics.
The manufacturer's systems.
Roadside cameras.
Toll records.
Parking systems.
Security cameras.
Individually, each may provide only a fragment.
Together, they can create something approaching a travel history.
The Legal Question Will Continue Even as the Technology Changes
The particular technology inside today's cars will eventually become obsolete.
Navigation systems will change.
Connected services will change.
Cameras will improve.
Vehicles may become increasingly autonomous.
The specific data generated by cars will change with them.
But the underlying legal question is unlikely to disappear.
Cars have become machines that can create information about their own use.
At the same time, the world around them has become increasingly capable of recording their movements.
That means a drive is no longer necessarily an event that disappears when the engine turns off.
Weeks, months or sometimes years later, pieces of that trip may still exist in different places.
And when investigators or litigants need to determine where a vehicle went, those pieces can become evidence.
The car may not literally speak.
But increasingly, the records surrounding it can tell a remarkably detailed story.