Since the bygone days of when electrically powered headlights replaced the primitive lamps fueled by either acetylene or kerosene on cars and vehicles, motorists have been able to travel much more safely and have far greater control over illuminating the darkened road ahead.
Electric headlights on cars first made their debut in the very late 1800s and then started to become more popular when Cadillac implemented them into their models in the year 1912. A short year later, other GM vehicles began following suit and from the years of 1920 to 1940, all cars manufactured featured replaceable bulbs made for each manufacturer's proprietary headlamp unit. Just after that, a brand new technology would become available that would help drivers make their way throughout the night with the greatest of ease.
Right before 1950, the introduction of round, standardized, sealed-beam units took the automotive industry by storm. Regulations all throughout Europe still allowed motorists there to use headlights with replaceable bulbs as they had in the past, but across the ocean in the United States, it was soon enacted that the round, sealed-beams were the standard. Shortly after that, rectangular sealed-beams made their debut and further improved the ability to better direct and aim headlights.
By the time the mid 1980s rolled around, U.S. made cars were a bit behind their European made counterparts where regulations were now in place allowing aerodynamic headlamps, also with replaceable bulbs for convenience and price concerns, to be used, taking the act of headlight aiming to a whole new level. These aerodynamic headlamps are still widely used today with the only recent improvement being the addition of high intensity discharge (HID) lights available on many makes and models of cars.
HID lights typically have a bluish cast to them, which is caused by two electrodes within the bulb and an arc of light bouncing between them. HID lights do illuminate a dark road better, but the risk of blinding other motorists is great if they aren't aligned and aimed properly. There are even regular bulbs with a blue hue to them to resemble HID headlights but these imitations don't provide the additional light.
In Europe, regulations mandate that high intensity discharge headlamps be used in cars with leveling systems in place to avoid dangerously impeding the view of other drivers. Many high end vehicles sold in the U.S. also come standard with a headlamp leveling system although it's not yet a requirement.
Whatever the type of headlamps used, in countries like Canada, headlight aiming on vehicles is regulated by Transport Canada, although each private manufacturer still holds their own lighting specifications to provide the ultimate in safe illumination. Wattage standards are also in place and high beams are allowed to emit no more than 70 watts while low beams should be no brighter than 60 watts. While there are bulbs with higher watts available, these are not allowed to be used on public roadways and must instead be reserved for off-road use.
Many motorists are unaware that factors such as vehicle load can have an effect on headlight aiming. When too much weight is in the back of the vehicle, the headlights will point more skyward. Some models of SUVs now have an automatic load-leveling suspension system that will take care of the problem for you. Other things like a fender-bender or minor collision can also cause the beam of headlights to be uneven.
To check the aim of your car's headlights yourself, park about twenty five feet, or seven and a half meters, away from a plain wall or garage door on a dark night and see where the aim of light is. For the low beams, the aim should be, of course, slightly lower than the aim of high beams and level with one another. When the headlamps are on the high beam setting, the aim should be bright in the center and evenly leveled.
If the aim is not even, have the lights adjusted and aligned for the best illumination and safest nighttime driving. The key is illuminating the widest part of the road ahead but without blinding any oncoming drivers. Check the car's headlamps yourself once a year or have your mechanic do it when you have the vehicle inspected.
Never forget the great importance of headlight aiming as not only does it allow you to see a portion of the upcoming road far better, but it also allows other oncoming motorists to see you in plenty of time to react if need be.