Telematics and insurance: what data your driving generates and who sees it

A modern car collects more about its own use than most owners realise. Some of that data stays inside and some of it leaves — and the difference between the two categories is worth understanding.

Three different systems people confuse

First, separate the concepts, because in everyday conversation they get lumped together.

The event data recorder. Captures a few seconds before impact, stores locally, transmits nothing. Covered in the black box article.

The emergency call system. Stays silent until a crash, then sends coordinates to the rescue services. Covered separately.

Telematics. This one transmits data regularly — to the manufacturer, and through them sometimes onward. That is the subject here.

Do not conflate them: the first two exist for safety and operate episodically; the third runs continuously and has a commercial dimension.

What manufacturer telematics collects

The set varies by brand, but typically:

• Location and routes.
• Mileage and time in motion.
• Speed, acceleration, braking severity.
• System states and fault codes.
• Charge or fuel level.
• Charging history on an electric car.
• Feature usage — climate, infotainment, driver assistance.
• Firmware update status — see the OTA article.

Why the manufacturer wants it: predictive maintenance, development statistics, service campaigns, and connected features such as remote preconditioning.

Usage-based insurance

A separate category, with explicit owner consent and a direct financial rationale.

How it works: the insurer receives data about your driving — through a dedicated device in the port, through a phone app, or directly from the manufacturer. Your premium depends on how you drive.

What gets scored:

• Harsh acceleration and braking.
• Speed relative to limits.
• Time of day — night driving counts as riskier.
• Mileage.
• Road types.

The upside: a careful low-mileage driver pays less.

The downside worth knowing in advance: the scoring is algorithmic and blind to context. Braking hard to avoid a collision looks identical in the statistics to braking hard through inattention.

A device in the diagnostic port

The most common arrangement for insurer telematics programmes is a dedicated device living permanently in the OBD port.

Two practical consequences are worth accounting for.

First — the battery. A permanently powered device draws current. Some of them do not sleep correctly, and on a car that stands for long periods that becomes a flat battery. Mechanics in parasitic drain diagnostics.

Second — the port is occupied. Connecting a diagnostic adapter means removing the device, and that is frequently logged as “equipment removed” under the programme’s terms.

Where the line runs between diagnostics and tracking

A fair question arises: if telematics collects data, does a diagnostic adapter not do the same?

The difference is fundamental and lies in two things.

Direction. A consumer diagnostic adapter reads data and shows it to you. It has no outbound channel — it is a radio bridge between the port and your phone. A telematics module transmits data to a third party.

Initiative. You plug the adapter in when you want to look at something and remove it afterwards. Telematics runs continuously without your involvement.

The distinction between reading and writing is covered in warranty and scanners — including why the adapter is worth unplugging after every use.

What an owner can do

See what is enabled. The manufacturer’s app usually has a section listing connected services with the option to disable some.

Check paired devices and accounts. Especially when buying used — the previous owner may still be listed. Why that matters beyond privacy is in the cybersecurity article.

Read the insurer’s telematics terms before enrolling, not after the first bill.

Remove third-party devices from the port when they are not needed.

Understand that some data is collected regardless of consent — fault codes, counters, and overheating history sit in the modules and are read at any service visit.

What this means when buying a car

A layer of checks that did not exist before:

1. Unlink the car from the previous owner’s accounts.
2. Check the port for a third-party device.
3. See which connected services are active.
4. Read codes and the module roll call — standard practice, covered in the used car protocol.

In short

• Three different systems: event recorder, emergency call, telematics. Only the third transmits regularly.
• Usage-based insurance scores algorithmically and cannot see context.
• A device in the port can flatten the battery and blocks the port for an adapter.
• A diagnostic adapter reads and shows you; telematics sends to a third party.
• Unlinking the previous owner is a mandatory step when buying.

Download the app — it reads data from the car and shows it to you, with no outbound transmission. ELM327 adapter, Bluetooth SPP, Android.