Intelligent speed assistance (ISA)

Since 7 July 2024 intelligent speed assistance has been mandatory in every new car in the EU. It warns you when you go too fast, but it is regularly wrong, and then the sign applies.

How does it work?

ISA determines the applicable speed limit from two sources: a camera that reads road signs, and map data from the navigation system. Drive faster than that limit and a warning follows: a symbol, a sound, or resistance in the accelerator.

It is emphatically not a limiter. You can always override ISA by pushing through the accelerator. It does switch itself back on for every new trip though: turning it off only applies to that one journey.

What the CBR asks about this

• You observe the situation yourself. If the alert differs from what the sign says, the sign decides.
• You respond to the warning according to the rijprocedure: adjust your speed, do not ignore it and do not brake abruptly.
• You know you can switch the system off when the situation calls for it, and that it will be on again at the next start.

This system falls under these guidelines from the Rijprocedure B:

Limitations: This is where the exam questions are

Map data lags behind

At roadworks, a temporary limit or a recently changed road, ISA often still shows the old speed. The sign at the roadside is then the only thing that counts.

The camera reads the wrong sign

A sign on a slip road, a sign on a lorry or an advisory speed can be picked up incorrectly. Matrix signs above the road are not always interpreted correctly either.

The system does not know your situation

ISA does not know whether you are towing a trailer or driving on a novice licence. The limit that applies to your vehicle can be lower than what the screen shows.

Warning is not limiting

Most versions do not intervene. The responsibility to actually adjust your speed stays entirely with you.

Three practice questions

Open one for the answer and the explanation.

At roadworks there is a temporary 50 sign. Your speed assistance keeps showing 80. Which one counts?

• The sign: 50
• The speed assistance: 80
• The higher of the two, so you keep up with traffic
• The average speed of the traffic around you

Correct answer: The sign: 50

Explanation: You observe the situation yourself and the road sign is decisive. Temporary signs are often not in the map data yet.

You switched ISA off at the start of your trip. What happens when you get in the next day?

• It is on again; ISA activates itself for every new trip
• It stays off until you switch it on again yourself
• It stays off, but only in built-up areas
• It is on and now limits your speed as well

Correct answer: It is on again; ISA activates itself for every new trip

Explanation: Switching off applies per trip. At the next start the system is active again. That is part of the EU requirement.

Can you drive faster than the speed ISA indicates?

• Yes, ISA warns but does not limit; you can override it
• No, the system hard-limits your speed
• Only on the motorway
• Only if you switch the system off first

Correct answer: Yes, ISA warns but does not limit; you can override it

Explanation: ISA is a warning system. Being able to push through it does not make your speed any less your responsibility.

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