Ok, here's how you fix it:

1. Calculate how many headlights need changing and how much it will cost
2. Create a fund for that amount.
3. Announce that in a 1.5 years headlight regulation changes and all cars need to adapt.
4. During annual checks verify the lights. If they don't comply with the regulation send driver to regulate/change them for free (covered by fund established in 2)
5. After 1.5 years do random checks. Each car that still doesn't comply gets towed. The owner can either pay for the tow and fixing the lights and can't recover their car.

Just saying there are new requirements would be unfair to poor people that bought a car before the new regulation. They would have to spend extra money now to fix something they are not responsible for.

Saying that car manufacturers have to fix all their cars would be unfair because they were selling car that complied with all regulations. This would not stand in court.

That's why there's no quick fix. Doing it fairly will be complicated and it will cost money. It's easier for politicians to ignore the issue.