Automatic Levelling will become mandatory for all passenger cars. What does it mean ?

In Geneva, during GRE 89 in october 27th of 2023, it has been decided to change headlamp aiming regulation in UNECE R48 text for all the countries that are accepting UNECE regulation (based on 1958 agreement).

You can find the final text within this link :

Microsoft Word - GRE-89-02e-Rev.3.docx (unece.org)

and you can find information about GRE within this link :

Working Party on Lighting and Light-Signalling - Introduction | UNECE

This new regulation will become mandatory for all new types of passenger vehicles in september 2027 and for all (new) vehicles in september 2030.

What will it change for you ?

Previously, this requirement was mandatory only for vehicle equiped with AFS (Advanced Front lighting System). Premium cars especially. To be able to do automatic aiming, the most common solution is to have sensors in the front and rear suspension system and a ''ECU", a sort of computer, able to send the vehicle pitch information to the lamp. Then lamp will be adjusted automatically by a motor in each lamp device.

If you have not this system on your car, you have usually a button on your dashboard. and still same concept for lamp aiming with actuator

Why did regulators changed from manual aiming to automatic aiming ?

Indeed it is quite simple. Who is using this button ? who is aware of this button ? Only lamp specialists ..

And if you do not adjust your lamp, you can glare oncoming drivers as below pictures (due to lamp misaiming)

It is just a question of Physics and Geometry.

When you put load in your vehicle, you will change the pitch angle of your vehicle. If you do not adjust your lamp, you will have exactly what we see on the picture above, this is the reason of this button on the dashboard ; button that nobody is using.

Then new regulation has been defined. Whatever the load in your vehicle, lamp will have to respect an aiming between -2,7% and -0,5% below horizontal line. For a lamp at a mounting height of 0,8 meter, lamp aiming will be restricting between -2% and -0,5%. As described in the schematics below, called "Blue Box" :

• Horizontal line is the lamp aiming value,
• Vertical line is the headlamp mounting height,
• The aiming value must be inside the quadrilateral shape.

Why do we have this restriction ?

I try to take an example to explain :

• Vehicle with a lamp at 0,8 meter height,
• Nominal aiming at -1% (steradian).

This vehicle will project light on the road at 80 meters (you must remind your geometry lessons some years ago with tangent properties)

In our example,

With the boundary conditions defined in the regulation, you can have light on the road from 40 meters to 160 meters (which are defined as the worst case to be still acceptable). If you do not see at 40 meters, it is dangerous for you who is driving (no visibility distance), and if you see at 160 meters or more, you have a high risk to glare oncoming drivers

If you are able to respect this requirement without leveling system, it is OK, you do not need anything. It is usually the case for sport cars. Chassis is so stiff (and trunk so small) that lamp aiming will never change.

But if you have variation in your pitch angle due to load, then automatic leveling is mandatory, as required in UNE R49, paragraph 6.2.6.2

“6.2.6.2. Headlamp levelling device 6.2.6.2.1. In the case where a headlamp levelling device is necessary to satisfy the requirements of paragraphs 6.2.6.1.1. and 6.2.6.1.2., the device shall be automatic

Good luck for the implementation !

Hope it helps you to understand a bit better this new requirement.

And for all innovative companies, if you are able to find other solutions that may replace the height sensor in the suspension system, you are welcome !