You don’t have to travel far down a darkened road before you see the bluish-white glow of LED headlamps coming your way. And increasingly, those LEDs are lighting the way for heavy-duty trucks. Fleets and OEMs alike are discovering that aside from the obvious illumination advantages they offer over halogen lamps, LEDs have a lot to offer drivers.
LED lights are actually quite different from conventional headlamps and halogen bulbs, which both apply an electrical current to a filament material. The filament burns brightly, and carefully aligned mirrors at the back of the bulb assembly project the light outward. An LED light is a light-emitting diode, which works in a markedly different fashion than a filament bulb. LEDs are actually small super-conductors, and the light they emit is created by electrons moving at an insanely high rate of speed through the superconductor material. Because LEDs don’t burn anything to produce light, they operate at much cooler temperatures than conventional vehicle lamps and last many thousands of hours longer, to boot.
“LEDs have been around since the late 80s, so they’ve been around for 30 years, but at first the cost was prohibitive,” explains Brian Norris, optical engineer manager for Grote Industries. “As costs have come down, light developers have more freedom to create new and improved lights, as you are starting to see more and more.”
Freightliner recently announced that from now on, LEDs will be the standard lighting spec’ on all its new trucks, including brake and marker lights.
“There are three main reasons we decided to go with all LEDs,” says Ryan Major, on-highway market analyst for Freightliner. “They last about 10 times longer than conventional bulbs and have less of a draw on a vehicle’s electrical system. But safety is the main reason: The white light they give off is a more natural color that the brain perceives as sunlight. And we feel there are definite advantages for drivers because of this characteristic.”
“LED technology is perfect for the ground vehicle transportation industry due to the fact that it is solid state, highly resistant to shock and vibration and operates on 75% less power than incandescent components,” adds Andrew Liuzzo, marketing communications specialist for Truck-Lite. The monochromatic nature of LEDs helps to make the lit appearance of signal lamps appear brighter than incandescent lamps that measure equal photometric output. In addition to illuminating more of the roadway, Liuzzo says wavelength produced by LED lighting falls within the melatonin suppression zone, due to higher intensity wavelengths that cover more of the color spectrum than halogen bulbs.
“This frequency has been proven to reduce drowsiness, similar to the way watching TV or other backlit screens before bed can negatively affect one’s REM cycle,” he notes.
“Furthermore, the improved visibility offered by LED lighting reduces the risk of accidents by illuminating both a longer distance and a broader width on the roadway, making unexpected obstacles appear sooner. Truck-Lite’s enhanced beam pattern created with state-of-the-art optical design software highlights more of the road without causing discomfort glare or disturbance to oncoming traffic. Not only does this significantly increase driver safety, but the reduced risk of accidents can also reduce maintenance and repair costs over the life of the vehicle.”
Warmer yellow colors like those produced by other lighting options have a tendency to add to driver fatigue, Norris adds. If the lighting color is more blue it gives better contrast (similar to daytime sunlight) and drivers tend to be more awake. Increased lumens is also a factor. This puts more light on the road in front of you. LEDs also better illuminate colors. Correct colors help objects, such as a deer, stand out from the background and be seen by drivers.
Equally important is that LED lighting dramatically exceeds the lifespan of traditional halogen bulbs, according to Liuzzo. In terms of forward lighting, he says a typical halogen lamp will have a B50 life rating of 1,000 hours on low beam (320 hours on high beam). By contrast, LED headlights have a life rating of 30,000 hours.
“Not only do the numbers speak for themselves,” he adds. “But the standards to which they are tested are also noteworthy: 50% of halogen lamps are permitted to fail and still receive the same life rating, while LEDs are expected to last the life of the vehicle.”
And that light stays consistent throughout the life of the LED, too. While the light output of halogen headlights can depreciate up to 25% over their first 100 hours of life, Liuzzo says LED headlights will produce a consistent light output over their lifetime, with only a 7% drop in lumen output over 25,000 hours.
“Coupled with Truck-Lite’s proprietary Diamond Shell 2.0 lens coating, LED headlights will stand up to the hazing and crazing that plagues typical headlamps,” he says. “As a result, the eliminated need for maintenance, buffing and polishing can only boost the fleet’s bottom line over the course of the truck’s life.”
And while LEDs cost more than conventional bulbs, Norris says fleets are finding that their long life more than justifies the added expends.
For starters, he notes, LEDs are also more energy efficient because they require less wattage to operate. This makes the wear and tear on a vehicle’s electrical system much less as it isn’t working as hard to operate. Also with lower current, a lower gauge of wire can be used. This allows for a lower vehicle weight and therefore, better fuel economy. And in normal operation, LEDs will last anywhere from 35,000 to 50,000 hours, which is roughly 10 times as long as incandescent lights. This means less downtime for light replacement and maintenance.
Another factor Major points to is better CSA scores for fleets using LEDs. They’re just so much more durable, there’s a lot less chance one will go out and give a DOT officer a reason to pull a truck over and cite the driver.
Liuzzo says Truck-Lite expects LED technology to continue to improve, while the lumens-per-dollar cost of LED technology will continue to improve, as will lumens-per-watts performance. “We foresee a future where LEDs will cost less,” he says, “while still offering the same great, if not better, performance in years to come.”