Those Blinding Blue Headlights
One of the more frequent vehicle equipment complaints that I receive is about headlight glare. I am told that they are horrendous to an oncoming driver and it is hazardous to be driving because they are blinding. Drivers want to take their eyes off the road or look to the side to avoid them. Are they legal?
The situation may be from one of three causes: poor design, a standard high intensity discharge (HID) headlamp, an improper retrofit, a standard light-emitting diode (LED) headlamp, headlamps designed for use on the left-hand side of the road instead of on the right as we drive here, or (most commonly of all) improper aim.
To encourage vehicle manufacturers to improve their headlight designs, the Insurance Institute for Highway Safety (IIHS) has begun to rate vehicles for headlight performance. According to them, headlights are still an afterthought on most vehicles in 2020, with only 6 of the 156 models having good-rated headlights across the board.
Tungsten filament sealed beam headlamps originated in 1940. They were improved by the introduction of the halogen sealed beam in 1962 and the replaceable halogen bulb in 1983. This change allowed for greater high beam intensity.
The next significant improvement was the HID headlamp that used a glass capsule of glowing gas to produce light instead of a heated tungsten filament. The system can be two to three times more efficient at producing light than the tungsten bulb. They produce more light in the blue end of the spectrum compared to the filament bulb which tends more toward the red.
It is the blue tendency that bothers drivers (especially older drivers) looking into these lights. Research is finding that the HID lamp does produce more discomfort glare. What's not clearly understood is the physiological mechanism behind discomfort glare (i.e., we don't know why glare hurts). But that's irrelevant to the question at hand; the fact is it hurts.
Bluer light stimulates 46% more discomfort than yellower light of equal intensity.
HID and LED headlamps produce wider beams, so a wider spread of positions in front of those lamps is going to be subject to glare if those drivers' eyes happen to intersect the high-intensity zone of the beam. That's a very common situation. Anyone ahead and to the right of the equipped car will experience some glare, especially if the observer's eyes are at equal or lower height than the headlamps in question.
That's just an unavoidable reality; low beams are low beams because they direct most of their light down and to the right.
The current innovation in vehicle headlighting is the LED headlamp.
Discounting the installation of lights that are either not meant for automotive use, eg: aircraft landing lights and non-standard LED lighting purchased on line, we have improper replacements widely available at local merchants. The words "for off road use only" or "check with local authorities before use" are often buried, unnoticed, in the packaging.
Over wattage tungsten filament bulbs were the first end user modification to create excessive glare. Any tungsten filament headlight bulb rated at more than 65W is illegal to use on our highways.
LED and HID capsules made to fit standard headlamp housings are available for purchase. These are illegal for use in British Columbia because they produce even more glare than proper HID lamp systems.
In the HID systems you have a capsule, reflector and lens all designed to work together. Capsules inserted into standard housings and reflectors do not distribute the light properly. This definitely affects oncoming drivers and could prevent proper vision for the driver of the vehicle fitted with them.
The LEDs in sealed units are not removable and the entire assembly must be replaced when they fail.
If you have a complaint about headlamps, Transport Canada is the government agency responsible.
If you want to learn more about why headlamp modifications are dangerous, visit Daniel Stern Lighting.
The AAA has tips for managing glare when driving at night.