I've been researching online recently about Electrochromic tint/windows. The possibilities are pretty much endless, it's just a thin layer that goes over a surface that is transparent until power is applied. I was thinking if there was a way to rig a laser jammer/detector countermeasure to an electrochromic headlights it'd be a pretty awesome (tho probably expensive) countermeasure for lidar, because you can choose the light transmittance and transparency from what I've read, so it doesn't have to completely black out your headlights, it could just tint at a transparency that is bad for 904nm but isn't exactly noticeable.