Actual report appears to be this one, from January / February 2025: https://www.trl.co.uk/Uploads/TRL/Documents/PPR2072---Glare-from-vehicle-lighting-on-UK-roa

Actual report appears to be this one, from January / February 2025: https://www.trl.co.uk/Uploads/TRL/Documents/PPR2072---Glare-from-vehicle-lighting-on-UK-roads---Supplementary-literature-review.pdf https://www.trl.co.uk/Uploads/TRL/Documents/PPR2072---Glare-... Finding participant / sample sizes for this is difficult, as it seems to be somewhere between a systematic review and a meta-analysis, but heavier on the recommendations than the analysis. (I went looking because the 'nearly all' thing sounded like a bit of a stretch. Not that I would be surprised if this were true, but I would be surprised if they could make that claim with much confidence.)