Understanding False & Nuisance Alerts

What is a false alert?

The system does not work as intended and gives an unexpected alert.

A false alert inaccurately interprets the surroundings and issues a warning when no actual hazard or unsafe condition exists. For example: a forward collision warning that activates on an overhead bridge instead of a vehicle.

What is a nuisance alert?

The system is working correctly, but the warning is unhelpful.

A nuisance alert detects a condition as it is supposed to, but given the real-world situation, the alert adds no value to the driver. For example: getting a blind spot warning when you have your turn signal on in a turning lane.

Examples

Here are a few examples.

Following Distance Alerts

Top-down diagram of an orange truck traveling on a curved roadway while forward sensors (yellow cone and green waves) track multiple blue cars ahead in adjacent lanes.

False Alert

Curved Roads

On a curved road, the system may track a vehicle in an adjacent lane as the vehicle directly ahead and issue a close-following alert, even though you are maintaining a safe distance from the vehicle in your lane.

Top-down diagram of an orange truck traveling on a curved roadway while forward sensors (yellow cone and green waves) track multiple blue cars ahead in adjacent lanes.

Nuisance Alert

Stop-and-Go Traffic

In stop-and-go traffic, close following distance alerts may occur frequently as vehicles travel close together or merge into the space ahead of you – even when you did not cause the close following distance.

Forward Collision Warnings

Top-down diagram of an orange truck traveling on a curved roadway while forward sensors (yellow cone and green waves) track multiple blue cars ahead in adjacent lanes.

False Alert

Shadows

Shadows cast into the road by trees, overpasses, or other large objects can confuse the cameras and cause the system to react as if there is a physical hazard.

Top-down diagram of an orange truck traveling on a curved roadway while forward sensors (yellow cone and green waves) track multiple blue cars ahead in adjacent lanes.

Nuisance Alert

Turning Vehicles

In stop-and-go traffic, close following distance alerts may occur frequently as vehicles travel close together or merge into the space ahead of you – even when you did not cause the close following distance.

Speeding Alerts

Roadside sign displaying a speed limit of 70 mph and a truck speed limit of 65 mph against an open landscape

False Alert

Sign Confusion

The system might incorrectly show the speed limit based on signs on other parallel roads such as service roads and express lanes or signs displaying minimum speed.

Yellow warning sign indicating a reduced speed limit ahead, with a posted speed limit of 55 mph.

Nuisance Alert

Speed Limit Change

Sometimes the speed system correctly recognizes a lower speed limit and issues an alert while you are already trying to slow down to follow the change.

Lane Departure Warnings

Close-up of worn double yellow centerlines on an asphalt roadway, with cracked paint and pavement deterioration visible

False Alert

Road Repairs

Poorly painted lane lines, pavement seams, and faded lines can cause the system to issue a false lane-departure warning even though your truck is still within the lane.

Top-down diagram of an orange truck traveling on a curved roadway while forward sensors (yellow cone and green waves) track multiple blue cars ahead in adjacent lanes.

Nuisance Alert

Construction Zones

Shifting lanes marked by cones or temporary markings where the old lane lines are still present can confuse the cameras. The system is correctly picking up the lane lines, but you know those are not the ones you should follow.

Blind Spot Warnings

Top-down diagram of an orange truck traveling on a curved roadway while forward sensors (yellow cone and green waves) track multiple blue cars ahead in adjacent lanes.

False Alert

Multi-Lane Roads

On multi-lane roads, the system may identify and issue an alert for a vehicle or guardrail that is further than one lane away from you as you try to change lanes.

Illustration of a blue car traveling behind two trucks on a multi-lane roadway, with a flashing amber turn signal visible on the truck ahead in the left lane

Nuisance Alert

Early Turn Signal

In situations where you see a vehicle quickly approaching to pass your truck, you may turn on your signal early while waiting for it to pass. The system may issue a blind spot warning because the vehicle is beside your truck, even though you do not intend to change lanes until the vehicle passes.

VTTI provides this information for general knowledge and education. However, VTTI does not guarantee the accuracy, completeness, or applicability of this information to any specific vehicle or situation. Drivers are strongly encouraged to consult their vehicle’s owner’s manual for detailed instructions and guidance on the proper use and functionality of these systems.