ive seen them on a lot of cars lately, but im not sure if they are legal or not…
Chief’s Domain - http://www.seas.ucla.edu/~ravi
Since they sell them at my local Checker Auto, I would guess that they are. In Colorado, at least.
They are legal.
I realize I’m generalizing here, but as in most cases, I don’t care.
-Dave Barry
Why wouldn’t they be legal?
I believe cheif may be referring to the newer mercury? vapor headlights, the ones w/ the funky blue tint. They have been around for a few years on euro cars and I understand they are quite common there. In a very few local areas they have been banned, but for the most part they are legal.
I imagine you’re talking about the arc-source headlamps we’re seeing on Lincolns and 'Benzes.
Generally, the law stipulates a sixty-watt maximum on automotive headlamps (off-road lamps of greater wattage must be covered while the vehicle is on the road). The law imposes no limit upon the actual light output (measured in lumens)–only on the rated input of energy (measured in watts).
Of course every headlamp you see on the road provides a greater lumenal output than a household 60W incandescent bulb. Over 90% of all headlamps on the road are halogens. In a halogen headlamp, a quartz bulb constrains pressurized halogen gas–iodine, krypton, or xenon–and application of voltage to a tungsten filament causes the filament to heat up (as well as to emit photons). The heat produced by the tungsten filament causes the gas pressure within the bulb to increase, resulting in redeposition of vaporized tungsten upon the filament. The result is brighter and longer-lasting than a household vacuum-bulb (in which the tungsten filament is gradually reduced to the breaking point). Halogen bulbs are not as common as in household use as vacuum bulbs because the pressure that halogen bulbs constrain makes them far more dangerous–they also suffer from related handling issues (fingerprints on halogen bulbs become hot spots where the bulb can overheat and weaken the glass.
Innovations in coating- and reflector technologies (and, to a lesser extent, filament- and gas technologies) continue to increase the specific light output of halogen lamps. Something of a technological revolution created what I guess you’re wondering about: short arc-source headlamps (a lot bluer than halogen, which in turn were a lot whiter than the yellowish lamps which predated them), descended from the longer-arc Osram HMI’s used for lighting movie sets and athletic stadia. These large, filament-free (the light is created by a sustained lightning-like exchange of charge between anode and cathode through an intervening medium of fluorescent gas) sources emit enormous torrents of light at a surprisingly low cost in energy. Their drawbacks, in the context of automotive applications, are many (and are familiar if you’ve ever arrived early to a concert or a basketball game): they take a long time to warm up to sustained intensity, to proper color, and to full brightness (gas temperature below optimum range); the quality of the color changes if the light is left on too long (gas temperature above optimum range); lights won’t restrike, meaning if the power is interrupted–however briefly–they have to cool down before they will light up again.
These drawbacks were addressed by the introduction of xenon as the gaseous medium between electrodes. Xenon arc discharge lamps are create immediate, brilliant light and are longer-lasting (no filament) and more economical (less energy, more light) than conventional halogen lamps. In fact, an arc source creates about 350% of the lumen output of a filament source of a given wattage. I understand that new-generation arc sources called high-intensity discharge lamps (HID’s) are coming out of development as we speak and are supposed to be even brighter. Further down the road is a quartz halogen (filament-source) bulb, trick-coated and xenon-filled, that is still brighter. All legal at sixty watts.
Boy, you ever get those things in your rearview mirror? Ack.
Yes, they totally suck and ought to be illegal IMHO.
It’s a case of eggheaded, safety-engineer-wonkishness triumphing over common-sensical everyday reality.
If we’re talking about those blue tinted headlights I see on Mercedes and Lexuses, I saw a new story the other day saying that they allow you to see some x% better and that supposedly some group is trying to get them required as standard equipment in all cars at some point in the future. I’m not sure if I’m remembering the story exactly right, however…
I wonder how hot they get. I know a home lamp of that type gets very seriously hot.