A recent innovation is the use of High-Intensity Discharge (HID) lamps, similar to the ones used in stadiums and streetlights.  These systems require an ignition coil to jump-start the current to 10,000 volts to establish a bright arc of current between two electrodes.  The two electrodes are enclosed in an "arc tube" together with xenon, mercury and other halides, causing the gases to illuminate.  The arc tube is capped with another quartz glass outer jacket to trap heat and filter ultraviolet radiation.  In contrast to stadium lighting which needs several minutes to warm up, a car's discharge lighting only needs about 0.3 second to equal the light from a halogen bulb. 

These gas-discharge systems provide more output while using up less current than halogen systems. Since they have no filament emitting lots of heat, HID headlamps can be reduced in size, which gives further advantages in aerodynamics and aesthetics.

You've probably seen E-class Mercedes with those futuristic blue beams of light.  Those beams are closer in color temperature to natural daylight.  They cut through fog and rain more efficiently than halogens, and make road signs and other cars much easier to see.  Several other car companies are adopting them, such as BMW and even Ford.  The downside?  These systems cost about $1000 per car, and companies like Mercedes do charge about that much for the system as an added option.  However, when enough models switch to this technology, the cost should go down rapidly until even economy cars will be equipped with them.

Now, you can't insert an HID bulb into a socket meant for a halogen.  The bulb shape and socket are completely different.  Also, a halogen system cannot supply the required voltage.  If you want to have a brighter beam, we suggest trying replacement halogen bulbs that are closer to HID in performance.  We tried PIAA's Plasma Blue (aka Super Plasma) bulbs in our test Cefiro and Accord and were impressed with the performance.  They aren't cheap at about P4000 per pair, but it's actually worth it in terms of safety and driving comfort.  PIAA claims a light output double that of the original bulb, in addition to a much higher color temperature. The installation in the Cefiro was particularly rewarding.  The beam now had a longer throw: illumination in near and mid-distances, as well as long-distances on high beam, was indeed much-improved.  We suspect the pre-facelift (1998-99) Cefiros sold here were European spec, because the beam cutoff is quite sharp.  The Accord, we were surprised to find, did not show such a dramatic improvement, maybe because its conventional halogen system was already quite bright.  Still, the light now has a purplish-white cast, and is quite closer in color to solar light. 

The Mercedes Vision SLR employs the 8-lamp system which corners as the car corners. The only difference is that, Mercedes makes this look good...offered with a xenon HID lamp too!
The new Mercedes CL line-up comes standard with xenon HID lamps. However, the implimentation is not just limited there, even the new facelifted E240 Elegance here in the Philippines  also has standard xenon headlamps. A good safety system to go with the 8-airbag system.