It's no secret that custom car enthusiasts often ignore the design advice that suggests form should follow function. We snub practicality in our quest for style, and sometimes even eschew simple safety measures to score cool points.

Take, for instance, taillights, those beaming beacons designed to protect our cars' rears. When designing a pleasing posterior, it's all too common to french in small lights mounted low on the body, or even in the bumper. While they may look cool, such lights often lack the attention-grabbing candlepower to which today's latte-drinking, DVD-watching motorists are accustomed. And the last thing you want is a plus-size SUV bearing down on your rear bumper simply because Sally Soccermom didn't notice you slowing down or signaling a turn.

Now, we're not about to suggest billboard-size blinkers for the rear of every custom, so the best advice we can offer is to make whatever lights you have as bright as possible. Fortunately, the street and custom rod aftermarket has a number of options for bringing maximum attention to your, ahem, rear. We thought we'd spend a little time discussing them here.

Light 'Em Up
As with any project or troubleshooting task, it always helps to start with the basics. That is, you want to make sure your taillights and brake lights are hooked up and functioning properly. Poorly grounded lights are a common problem on old cars, as well as those that have been recently rewired or repainted. It's also important to check your brake light switch to make sure it's working well. Replacing an old pressure-activated switch with a new low-pressure version or a mechanical switch is always cheap insurance.

One often-overlooked tip is perhaps the simplest: making sure your taillight lenses are clean and clear, and the reflectors are, well, reflective. This is especially important on cars with 50-year-old taillights, but it's also worth noting that some new reproduction lenses may actually be darker and more opaque than OEM offerings. Plastic polish can often be used to help clear up scratched or dull original lenses, while it's common to use a bit of silver paint on the reflector to maximize the taillight bulb's light distribution.

Once your wiring, housings, and lenses are in order, it's time to figure out the best bulb option. Standard incandescent bulbs may be perfectly adequate in many applications. If you want something brighter for OEM-style lights, you have three basic options: brighter incandescent bulbs, halogen replacements, and LEDs

Brighter Bulbs
The original incandescent taillight bulbs in your car work the same as standard household bulbs. That is, they generate light when electricity flows across a tungsten filament, heating it up. The most common taillight bulb-the 1157-actually has two filaments, one for the taillight and another for the brake light.

It makes sense, then, that one of the simplest ways to make your taillights brighter is to swap out the stock bulbs for brighter versions, much like you'd step up from a 40-watt bulb to a 60-watt bulb in a household light. Several companies offer brighter 1157-style replacement bulbs, which use different filaments that draw more amperage and burn brighter. Of course, heat is a byproduct of light, so these bulbs also get hotter than standard bulbs-hot enough to discolor or even melt some plastic lenses, and sometimes even scorch paint. Most suppliers recommend using them only with glass taillight lenses. Steve Watson, at Watson's StreetWorks, also suggests drilling small ventilation holes in the taillight housing (provided the housing is inside the car, protected from moisture) to help dissipate heat from extra-bright bulbs.

Another option is to replace your standard bulbs with one of several available halogen bulb offerings. Some of these bulbs are designed to fit in standard 1157-syle sockets; others need special sockets wired in. Halogen bulbs still use tungsten filaments, but enclose them in quartz that is back-filled with halogen gas. The halogen virtually eliminates oxygen inside the bulb, which helps keep the filament from corroding and failing. Thus, the bulbs last longer. The halogen also allows the filament to run hotter and generate brighter light. The downside, again, is the heat-halogen bulbs put off more heat than conventional filament bulbs, so they are best used with glass taillight lenses.

LEDs
In recent years, LEDs-or light emitting diodes-have offered yet another lighting alternative. Unlike conventional bulbs, LEDs do not use filaments to generate light. Instead they produce an electrical arc that jumps across a gap, and a reflector behind the arc directs and focuses the electric light. LEDs are much more efficient than incandescent bulbs, so while they produce bright light, they generate very little heat.

LEDs are quite small and their light is very focused, so they are typically bundled in groups for automotive lighting applications. For instance, an LED replacement for an 1157 bulb may have anywhere from 10-25 individual LEDs grouped together and fitted to a regular bulb-style receiver. Several manufacturers group LEDs on cards to fit specific taillight applications, such as '50 Pontiacs, '55-57 Chevys, or early '60s Impalas. Such cards allow the LEDs to be placed so they'll distribute their light most effectively. For the record, LEDs do not produce so-called "white" light; they generate light in specific wavelengths, and generally give off a red, amber, or blue glow.