ECE Guidelines Explained – Part 2

The minimum light intensity for daytime running lights is 400 CD. This is comparable to a bright LED Christmas light. It is not blinding but clearly visible in the dark. The maximum light intensity should be 1200 CD and the colour of the light must be white.

 

Brake lights must emit red light. Brake lights at the rear of the vehicle should have a minimum luminous intensity of 60 CD. If the brake light is behind the rear window (third brake light), it should emit at least 25 CD measured from outside the vehicle.
The difference in the brightness between the third brake light and the other two brake lights on the back of the vehicle is in the placement. The third brake light is higher on the vehicle and therefore closer to the eyes of the person behind it. It needs to be less bright to avoid dazzling the rear driver.

 

Direction indicators are at the front and rear of a vehicle and must emit amber light. The standards for light intensity are different for each side.
A distinction is also made between the light intensity of indicators on vehicles and on trailers. The idea behind this is that a trailer does not need bright indicators because the towing vehicle already has bright indicators. Only when driving behind a trailer, it is nice to see that it wants to take a turn. So the trailer should also have blinkers. To put less strain on the tow vehicle's battery, the minimum brightness for a trailer indicator is lower (50 CD) than for the vehicle (175 CD). The maximum light intensity ranges from 280 to 500 CD for trailers and from 1,000 to 1,200 CD for cars and trucks.
A special requirement is for a warning signal to be activated if an indicator fails (e.g. faster clicking).

 

The marking lights also apply to more than one side of the vehicle: side or rear. This means that the light intensity varies between a minimum of 4 CD and a maximum of 25 CD.
The colour for side markings must be amber. Marker lights at the rear must be red (combined with the rear light).

 

Reversing lights must emit white light with a minimum light intensity of 80 CD. Depending on the light distribution angle of the lamp, the maximum light intensity is between 300 and 8000 CD.

 

The mandatory colour of a rear fog light is red. The minimum light intensity is 150 CD and a maximum of 300 CD for the standard rear fog lights and a maximum of 840 CD for the adaptive rear fog lights (which can be brighter when braking hard in fog).

 

So much for the light intensities. But inconvenience to other road users can also be caused by incorrect installation of the lamps. That is why ECE R148 also contains standards for the installation and adjustment of lighting. But that is a completely different technical story. See the EU website for that.