Driver drowsiness detection

The coffee cup on your dashboard is the easiest exam topic on this page, because there is exactly one right answer: stop and rest. Every other option is wrong.

How does it work?

The system does not measure how tired you are. No car can. It looks at your behaviour: small, late steering corrections, drifting within your lane, how long you have been driving and sometimes the time of day. From that pattern it infers that you are probably getting tired.

When it recognises that pattern, a coffee cup or a text message appears advising a break. Some cars use a camera that tracks your eyelids and head position; those are more reliable, but rarer.

What the CBR asks about this

• You respond to the warning according to the rijprocedure. For fatigue that means: stop at the next safe opportunity and take a break.
• You keep assessing your own state. No alert does not mean you are rested.
• You stay responsible for the decision to drive on. An ignored warning weighs heavily if something happens afterwards.

This system falls under these guidelines from the Rijprocedure B:

Limitations: This is where the exam questions are

It measures steering, not fatigue

On a quiet, straight motorway with few steering corrections the system may see nothing while you are genuinely tired. Conversely, a windy day can produce false alerts.

It triggers late

By the time your steering changes, fatigue is often well advanced. The alert is a last signal, not an early warning.

Short trips and low speeds fall outside its scope

Most systems only become active above a certain speed and after a certain driving time. In town they do nothing.

Coffee is not the solution

The symbol is a pictogram, not advice to press on with caffeine. The only thing that fixes fatigue is rest.

Three practice questions

Open one for the answer and the explanation.

The coffee cup appears on your dashboard. What is the right answer per the rijprocedure?

• Stop and take a break at the next safe opportunity
• Open a window and drive on
• Dismiss the alert and reduce your speed
• Drive on to your destination, it is only advice

Correct answer: Stop and take a break at the next safe opportunity

Explanation: You respond to warnings from assistance systems according to the rijprocedure. For fatigue, rest is the only thing that works.

What does a standard drowsiness detection base its warning on?

• Your steering behaviour and how long you have been driving
• Your heart rate through the steering wheel
• How long you slept according to your phone
• How often you blink

Correct answer: Your steering behaviour and how long you have been driving

Explanation: Most systems infer fatigue from late, small steering corrections and time on the road. They do not measure your state directly.

You have had no warning, but you notice yourself getting tired. What do you do?

• Stop and take a break; your own observation comes first
• Drive on, the system would have warned you otherwise
• Set the drowsiness detection to be more sensitive
• Switch on the cruise control so you have less to do

Correct answer: Stop and take a break; your own observation comes first

Explanation: The driver observes the situation themselves. The absence of an alert says nothing about how rested you are.

Written on the basis of the official CBR Rijprocedure B. These are not real exam questions.