Well, the latest and the greatest is the LED light. Small, bright, low current draw and easily configured into most any shape or size, it fits the need for emergency vehicle lighting very well. What are the other advantages of LED lighting?

First, LED's, when properly manufactured, are extremely reliable. They have no filament to shake loose or burn out and no thin glass lens to shatter. Light arrays are either circuit board mounted using a shock resisting method or are "potted" meaning they are encapsulated in an epoxy that seals them against moisture, vibration and damage. All that sticks out are the positive and negative power leads, a pattern changing lead and perhaps a synch lead if multiple lights are to be synchronized.

Second, LED's provide intense light in a color spectrum that is essentially pure. That means the light is more visible to more people. In fact, I've heard of people who cannot distinguish between amber and red strobe or halogen lights being able to discern the color differentiation in LED's. I believe that is simply due to the purity of the emitted light. Plus, LED's produce colored light without filters, and filters reduce light output.

Next. LED's require very little current to operate. You can operate an array of hundreds of LED's with the same amperage it takes to operate one incandescent bulb. The old rotating beacons often took dozens of amperes to support their operation, and sometimes would completely drain a vehicle battery if the vehicle fast idle circuit didn't engage to boost the charge rate. And, you had to leave the vehicle running to assure the lights would not dim. Not so with LED's.

LED's trigger very rapidly, making their on and off functions instantaneous. Thus, they make great lights for stop and turn signals, as well as emergency lighting. Solid-state flashers allow these LED's to flash in patterns mimicking strobe lights with less current, longer life and greater reliability. In many cases the LED's produce visible light output that is equal to that of the strobe. Notice I said "visible", since LED's are rated totally different than strobes and you're not going to find 2.5 million candlepower LED's anywhere.

  (See my guide on strobes for more information on strobe power)

Compared with strobe lights, they last longer and are more reliable in the long term. However, when mounted behind colored lenses, such as tail lights or turn signals, they do not have the "punch" that a 22.5 watt powered strobe bulb has in getting the light signal out. In clear lens operation, they do provide good signal power.

Another point to make is that LED's with colored lenses over white LED's will reduce the overall light output, so use the correct color LED's with no lenses if they are designed that way, or clear lenses if necessary. Some of the brightest LED's have a clear lens as part of the assembly and it is molded in when the light is assembled to provide protection as well as enhance visibility. Others, such as lightbar LED's are mounted behind clear Lexan in the bar. Plus, clear gives them more stealth and less obtrusive in daily operation. Also, consider the generation of LED you will buy. Gen III provides more light that GEN I or GEN II, but if money is a big concern, the GEN II's do very well.

Remember that all lighting is directional. No matter what you hear about beam width or anything else, if you misdirect the light when you set it up, it will be ineffective. After installation, view the lighting from the position other drivers will see it from. Remember that trucks and vans will have to see it as well as sedans and sports cars. Walk back several hundred feet or more and look at the lighting. Is it effective? Look at it both day and night. Lighting that blows your socks off at night, yet can't be seen during the daytime, is dangerous at best. It will give you a false sense of security and expose you to greater levels of danger. Some lighting provides a wider beam, which is helpful in spreading the available light left and right. But remember that doesn't usually help if you recess the lights deep within the grille.

Look at what you real needs are. How many lights do you need, how will they be used and will they be effective? Buy the lighting that will best serve your needs for every occasion. For example, my vehicle has LED's in the grille and rear deck, a LED directional arrow and warning bar in the rear deck, and strobes in the front cornering lights and the tail lights. Plus an additional pair of strobes on the rear deck with a separate power supply for additional light if needed.

Finally, beware of "cheapie" equipment and low grade LED's, flashers, etc. Look for heads and equipment that is professional grade, if you are going to be using them for responding to emergency situations. This doesn't mean that you can't find a good bargain on eBay on Whelen, Federal, Code 3, Sho-Me, Galls or other high quality gear, but beware of the cheap imports that will leave you literally "in the dark" when your life, or that of others, is at stake. A unit that quits because it's poorly constructed is worse than no unit at all, because you've come to depend upon it. If you had no lights at all, at least you'd know that nobody could see you! I have tested low grade strobe power supplies and had them quit flashing in a few hours and even a few minutes. Lots of people are building custom LED units for sale on eBay, and I'm sure there are some good ones, and some bad. But, when you buy homemade, you're not buying professional grade from a major manufacturer with the R&D facilities to back up that equipment. Return privileges and warrantees on junk mean nothing in the middle of a rainy or snowy night when you're sitting with no emergency lights.

Light assemblies made in China, Taiwan and other places are often "knock-offs" of similar US made equipment. You'll likely not know where the light was made until you receive it, as many do not tell you this is an import; or if they tell you it's an import, don't tell you from where. In fact, some don't even have labels telling you who made them, so you have to guess, but you know it's not US made. The nice plastic case that cracks after a short time or the rugged looking aluminum case that conceals cheap LED circuitry that fails due to vibration won't help you when you need it most. Again, there are some decent lights that are imported by a few people but I don't have the facilities to put them through thousands of hours of burn time tests, and I suspect neither do they, so in my opinion it's still a gamble on how long they last in emergency use.  

A September 2007 update on an amazing light, but alas, no longer made. The Sho-Me Octa-Brite 90 light is amazingly bright and containg eight one-watt Generation III LED's that spread light at 30 degrees vertical and 90 degrees horizontal. That means that exact aiming is not a problem and being off axis when mounting is okay. Traffic coming at you off center still sees the same brilliant warning as those coming straight on. Combined with the 11.1005SF multi-pattern strobe flasher, this setup is really blinding. Plus, the light housing is cast aluminum, not plastic! Cast, not stamped or cheap extruded and made in the USA! I installed them in the lower grille of my new 4x4 and it's the best lighting I've ever had, bar none. Much better than the 4 Sho-me Micro-Lites that were in my Crown Vic, which had 40 LED's in each light. The closest thing to these is the Sho-Me Hexa-Brite 90 lites which are essentially the same, but with 6 LED's per head rather than 8. Why they stopped making the Octa-Brites I don't know but they really are great.

My caution follows:

After you jump, it's too late to wish you bought the better parachute!  Same with emergency lighting!

Be safe, and be seen.