But apparently they are much worse in clear weather, so the new EU regulation require white lights:
> Whilst yellow light improves visibility in wet or foggy conditions, it can also be harder to see with yellow lights in clear conditions. As a result, many vehicles today use yellow lights only as fog lights.
> White lights are the most popular colour for the headlights of today. In many countries, headlights are no longer allowed to be yellow and must be white in colour. European regulations, for example, require all new vehicles to be manufactured with white headlights.
I can only find that claim on a Powerbulbs store blog post.
Current UN regs do indeed require white. Definitely not "much worse", more like simply different. They were very yellow, right out there with sodium lighting and obliterated colour acuity. So highly unlikely to be coming back. :)
> Whilst yellow light improves visibility in wet or foggy conditions, it can also be harder to see with yellow lights in clear conditions. As a result, many vehicles today use yellow lights only as fog lights.
> White lights are the most popular colour for the headlights of today. In many countries, headlights are no longer allowed to be yellow and must be white in colour. European regulations, for example, require all new vehicles to be manufactured with white headlights.