Many discount the frequency and severity of blindingly bright headlights. NHTSA and the IIHS tend to blame "headlight mis-alignment" and that blue, 6500K lights "feel brighter even though the aren't any brighter".
The best way to determine the accuracy of these statements is to obtain information from real-world testing. The real-world glare levels we are seeing on the road is easy to demonstrate by simply driving with a lux meter, held at eye-level at night.
The results are below.
For context, NHTSA claims to want to maintain glare levels (the amount of light in your eyes from on-coming traffic) to below 1 lux.
The IIHS has a goal of keeping glare to less than 6 lux for straight roads and less than 10 for curved roads.
The massive variation in glare levels and many data points above 10 lux shows that there is clearly something going on here.
You're not crazy. Headlights are bright. You are being blinded.
NHTSA has a study that their peak glare illuminance profile for a properly aimed headlight. An illuminance profile is the time vs glare curve as an on-coming vehicle approach's. OwMyEyes was able to paring the lux-meter readings with a dash-cam to determine the illuminance profile from our on-road trials.
We have plotted the NHTSA Max Glare from a properly aimed headlight against a peak glare of 5.6 lux and 15.3 lux. The amount of glare on our roads is clearly above the max glare from a properly aimed headlight.
Glare Dosage is the integral of the time-glare curve and presents the curve as a single value. NHTSA's worst-case glare (from 12 headlights, and 1.5 degree up angle) is 6 lux*seconds.
The integrated illuminance profile of the 5.6 lux peak glare curve results in a glare dosage of ~7 lux*seconds.
The integrated illuminance profile of the 15.3 lux peak glare curve results in a glare dosage of ~14.6 lux*seconds.
Both glare dosages exceed the NHTSA worst-case (1.5 degree mis-alignment and high mounted headlight) glare dosage.
Not only this, but the worst-case NHTSA glare-dosage represents only the 75th percentile of glare-dosages we see on the road. Fully 25% of on-coming car events have a higher total glare dosage. This "worst-case" is now nowhere near worst-case.
Something else must be going on.
OwMyEyes is attempting to determine what with by determining the CAUSE of high glare events.