Some years ago, there was considerable debate concerning retrofit HID sets for autos. This was because of the intolerable glare shaken off by badly designed HID retrofit systems. An understanding of the physics behind architectural lighting design optics reveals that halogens as well as Xenon bulbs generate light in different methods, thus influencing exactly how a certain reflector housing and also lens is created. Simply put, H4 headlamps carry out optimally with halogen light bulbs and also HID bulbs carry out ideal with reflectors as well as lenses designed for them. For an HID user, the 300 percent rise in light result can just be an advantage, particularly in suv or backwoods where the only light when driving is the one that the lorry's lights are throwing away.
Nevertheless, having concealed lights even on low beam is equivalent or even greater than having halogen lights on high, which is why glare is a very real concern for oncoming vehicles. As mentioned, halogen and HID systems are fundamentally different because while halogens produce light through a filament, HID systems produce light through a gas arc.
In practical terms, what this means is that a reflector which has been designed to catch and reflect light given off by a halogen bulb will reflect light in the wrong places when used with a Xenon, or HID, bulb. If you as a car owner feels the need for an HID system, at the very least aim the lights lower than normal so that your much brighter lighting design consultancy do not hit an oncoming vehicle's driver in the eyes.
In fact, it has been deemed that the only correct way to retrofit an HID system is to use a whole assembly which has been designed for an HID bulb from the outset. Reacting to the early complaints of too much glare for oncoming drivers, the big automotive lighting manufacturers have already come out with projector HID systems that can be retrofitted to older cars. For older cars with halogen systems, DIY types have managed to modify their vehicles' reflectors to better accommodate the beam patterns of Xenon bulbs.
Usually, this involves baking the lighting assembly to remove the lens, cutting/reshaping the reflector and then resealing the lens and reflector assembly with silicone. Fortunately for the buying public, HID systems have become commonplace in newer cars and modifying your system can be as simple as replacing your OEM Xenon bulb with one having a higher wattage.