Are lights not checked during the NCT so should get resolved eventually?
They are, but there are growing numbers who feel that some approved LED / HID lights, even when properly aligned are causing glare issues to the point where it becomes a safety concern. It's an international issue, hence the UNECE involvement.
Now, there's an element that many of those complaints are coming from those of us of a certain age, normal degradation of the eyes and the increased blue light content of modern bulbs is problematic for older eyes. It was long before the introduction of these lights that my own mother stopped driving at night as she couldn't handle the glare. The issue of glare itself isn't a new one, and along with brighter lights, populations are ageing and more people are driving.
So, there are two sides to the argument, modern brighter lights significantly improve visibility for the driver, but many older drivers find their glare more problematic.
Reducing brightness will result in more collisions due to failure to spot hazards, but leaving them as they are may also be causing accidents. Is there a point at which reducing brightness by X% from the current max results in an optimal middle ground where they are bright enough to avoid a significant number of incidents while not causing more? Much of the data (
example) shows significant reductions in nighttime collisions with brighter lights but little or no change in incidents where glare was recorded as a factor.
Perhaps the solution may even include stricter requirements for driver eyesight testing and bring in tests to measure glare recovery time, contrast sensitivity, etc..