Tailgating detection

GM of Operations

Published 12 September 2026

Tailgating detection uses a road-facing camera to estimate the gap to the vehicle ahead, expressed as the time it would take to reach it at current speed, and raises an alert when that gap falls below a configured threshold.

Tailgating detection, also called following-distance monitoring, is an ADAS function. The camera identifies the vehicle ahead, estimates the distance to it, and divides by current speed to produce a headway figure in seconds. When headway drops below the configured threshold for a sustained period, the device warns the driver in the cab and flags the event. It is measured in time rather than metres because a safe gap at 30 km/h is dangerous at 100 km/h.

Why it matters

Following distance is one of the few camera-detected behaviours with a direct and well-understood link to rear-end collisions, which makes it one of the more defensible things to coach on. It is also one of the highest-volume alerts in congested or urban driving, where closing the gap is often unavoidable rather than careless. A fleet that flags every sub-threshold moment in city traffic will bury the genuinely risky sustained tailgating in noise.

How MapTrack helps

MapTrack records flagged events against the asset they came from, alongside the inspection, maintenance and cost history for the same vehicle, so event volume can be assessed as a review workload as well as a safety signal.

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Frequently asked questions

Is tailgating measured in metres or seconds?

Seconds. Headway is the time it would take to reach the vehicle ahead at current speed, which is why the same physical gap can be safe at low speed and unsafe at highway speed.

Why does tailgating detection alert so often in traffic?

Congested driving naturally produces short headways that the driver cannot avoid. Filtering by sustained duration and by road type matters more than the raw count.

Related terms

ADAS (advanced driver assistance systems)

ADAS is the umbrella term for systems that sense the road environment and either warn the driver or intervene. In a passenger car this includes autonomous emergency braking and adaptive cruise control. In a fleet aftermarket camera it usually means warning only: the device detects a risk such as a short following distance, a lane departure or an imminent forward collision, and alerts the driver in the cab while flagging the event for review. ADAS is the outward counterpart to a driver monitoring system, which looks inward at the driver.

AI dash cam

An AI dash cam is a connected vehicle camera with enough on-device processing to run computer-vision models against the video stream in real time. Road-facing models typically cover following distance, lane departure and forward collision risk. Driver-facing models cover distraction, phone use, drowsiness, smoking and seatbelt use. The device decides which moments are worth keeping, saves a short clip either side of the trigger, and uploads it with the matching GPS and sensor data. The word AI describes where the analysis happens, not a difference in image quality.

Harsh braking

Harsh braking is one of a small family of accelerometer-derived driving events, alongside harsh acceleration and harsh cornering. A telematics device measures the rate of change in speed and raises an event when it crosses a threshold set in the platform. Thresholds are configurable, which means the same driving can produce very different event counts on two systems, and event counts are not comparable between vendors unless the thresholds are known.

Cite this definition

Writing about this topic? You’re welcome to quote this definition. Here’s the wording to use so your readers can find the original.

Tailgating detection, also called following-distance monitoring, is an ADAS function.

Short attribution: MapTrack Glossary: Tailgating detection, https://www.maptrack.com/glossary/tailgating-detection
Reference list: MapTrack. (2026). Tailgating detection [Glossary definition]. Retrieved from https://www.maptrack.com/glossary/tailgating-detection

Free to reuse with credit under a Creative Commons Attribution 4.0 licence. If you’d rather link straight to it, the page is https://www.maptrack.com/glossary/tailgating-detection.