This story appears in the May 30 print edition of Transport Topics.
Light-emitting diodes, commonly known as LEDs, are a popular aftermarket addition for interior, backup, fog and other lighting needs on large trucks. And, according to several truck makers and their suppliers, they are destined to become, eventually, the headlight of choice for the trucking industry.
Currently, halogens and high-intensity discharge, or HID, lamps are most commonly used for headlights. Halogens continue to make good headlamps for heavy-duty trucks, especially because they have been improved by a number of technological tweaks, Preston Feight, chief engineer for Kenworth Truck Co., Kirkland, Wash., told Transport Topics.
Although Feight said these headlamps “do an outstanding job with low-energy output,” he also said he sees opportunities in forward lighting for LEDs “maybe in the next three-to-five-year window.”
But Brad VanRiper, senior vice president of research and development and chief technology officer for Truck-Lite Co., Falconer, N.Y., said the technology already is here.
VanRiper said the company introduced LED headlamps more than three years ago. They were designed to replace any standard 7-inch round headlight that runs on 12-volt applications.
Truck-Lite has sold LED headlamps to the military since 2007, VanRiper said, adding that “several trucking companies of substantial size” are testing the product.
“Readiness is so critical to the military market, and we know that readiness is part of the heavy-truck market. . . . Neither [the military nor trucking] can afford having to deal with forward-lighting failure,” he said.
The LED headlamp “was not an easy technological problem” to overcome VanRiper said. He added that LEDs have a longer life span, a warmer, more natural light, and are more resistant to shock and vibration.
An LED headlamp is more expensive, but it lasts much longer, he said: “The best halogen [lamp] gets 1,950 hours. [LED] lamps get well over 10,000 [hours]. They get more than five times the life of the best-rated halogen.”
An HID lamp, on the other hand, “has a premium cost. It’s high-voltage and requires a ballast,” VanRiper said, adding, “we don’t make any for the truck market.”
Halogen lighting is suitable for the heavy-truck market, but VanRiper said that market is mature and “may go into decline in the next decade because [incandescent] bulbs are going to disappear, as we know it.”
Companies are federally mandated to stop manufacturing incandescent bulbs by 2014, meaning that “it’s going to be LED or fluorescent. So there’s a pressure to improve LEDs,” he said.
However, David Szatkowski, director of marketing for United Pacific Industries Inc., Carson, Calif., said his company produces a wide variety of headlamp kits, and “every one of them is halogen.”
Some kits include supplementary LED lights along with the headlamp, but “the LED [light] does not replace the headlight itself,” he said. “That’s not going to happen soon.”
Szatkowski and Feight said LED technology is not yet up to the task of powering headlamps, a vehicle’s critical source of illumination.
“The challenge for LEDs is the ability to emit light farther than a few feet. For a long time, LEDs have been challenged because they have a difficult time pushing light any distance,” Szatkowski said.
Competing with incandescent lights requires large numbers of light-emitting diodes, and that, he said, means “it’s going to get hot” behind the light — so hot that manufacturers need to add some type of cooling mechanism.
Halogens are incandescent lamps with tungsten filaments. An HID lamp establishes an arc between two electrodes in a gas-filled tube, causing a metallic vapor to produce radiant energy.
Peterbilt Motor Co., Denton Texas, has come down on the side of halogen lighting, with an option for HIDs, for its new Model 587. The company introduced the Model 587 at the Mid-America Trucking Show, which opened March 31.
Two kinds of new technologies have brought about improvements in halogen lighting, said Scott Conway, an engineer who designs headlamps for Peterbilt and its sister manufacturer, Kenworth, both units of Paccar Inc., Bellevue Wash.
Peterbilt’s Model 587 uses “the best of one world for high beams and the best of the other for low beams,” Conway said.
The high-beam halogen lamp has a complex reflector, sometimes called a free-form reflector, “so we’re throwing as much light down the road as we can,” he said.
The low-beam halogen and HID lamps use projector modules that allow for even distribution of light on the road and result in less driver fatigue, Conway explained. A bulb shield blocks off glare for oncoming drivers and puts more light on the road.
“You can tailor the beam pattern so there’s more light on the right-hand side of road than the left,” he said.
The high-beam lights are added to the low beams, and “there are special things we’re able to do to get the high beam and the low beam to match each other so there’s no overlap or no dead area. That really reduces driver fatigue,” Conway said.
The HID lamps “start slowly but there’s more light, a whole lot more light,” he said, adding that a halogen bulb lasts 2,000 hours of life, but an HID light has up to 3,000 hours of life.
“It’s a lot brighter, and it lasts a lot longer.” Conway said. “It costs a little more upfront, but it’s a more consistent product. If you lose a headlamp, you’re out of service, you’re not making money.”
Conway said that the while LED headlamps may work for “cutting-edge passenger cars, for heavy-duty trucks, their disadvantages outweigh their advantages.
“LEDs right now are really expensive,” he said. “They last about 50,000 miles, but you have to replace the whole headlamp.”
Some companies have put in fans to reduce the heat generated by LED lamps, but “we don’t want to offer anything like that. We want to cool by air flow,” Conway said.
Conway believes that the beam pattern created by LEDs contributes to driver fatigue.
“We have built LED headlamps. We follow the technology, but we’re waiting for the sweet spot where the cost comes down to where replacement is affordable and where the robustness comes up so it is durable and the performance is exceptional,” he said. “Instead of being first, we want to have the smartest product.”
Attempts to obtain comments from Daimler Trucks North America and Volvo Trucks North America were unsuccessful.
There may be debate over the effectiveness of LEDs in headlamps but not about its role in other types of truck lighting, where the diodes are used extensively.
With the costs of LEDs coming down and the cost of incandescent bulbs going up, “in another three or four years, I suspect, it will be all LEDs” on trucks, said Eric Thorstensen, director of OEM sales for Grote Industries Inc., Madison Ind.
“There are a lot of positives — long life, power consumption and LEDs offer color that is better for driving, less stressful on the eyes,” he said.
Thorstensen said his company produces a wide range of LED lighting — “anything on the outside of the truck that’s not white: reefer lighting, forward lighting, work lamps, backup lamps, fog lamps.”
LEDs are more expensive initially, but most fleets understand that they will make up the cost in the long run, he said, noting that an incandescent taillight lasts about 1,000 hours, but an LED taillight can last 50,000 to 100,000 hours.
“You can install it once and forget it,” Thorstensen said. “Fleets know if they have a truck with a light out, that truck is not available to go down the road. They know how much it costs them per minute.”
Most trucks still use incandescent interior lighting, he said, but “they are heading toward all-LED interiors. I predict that will happen in the next four or five years. . . . It’s an easier color on the eyes.”
United Pacific’s Szatkowski said he sees a bright future for energy-efficient LED lighting as costs continue to come down and the product is more readily available on the market.
LEDs lighting is especially popular for aftermarket truck parts, he added.
The customization “provides the truckers an identity for their products,” Szatkowski said. “It’s mostly decorative, but [the lights] also provide safety” through increased visibility.
Truck-Lite’s VanRiper said he sees LEDs available “for just about any need. . . . The days of light bulbs [on] trucks are numbered. Almost every company wants LEDs from the front of the truck to the rear of the trailer.”
Before 1991, in the era of only incandescent bulbs, lighting ranked “in the top 10 of frequency of failure,” VanRiper said. “Now, for many fleets, it has dropped out of the top 100.”
But he said he still sees room for improvement.
“Once you get LEDs on the vehicle, what is the next weak link?” VanRiper asked.
His answer, gleaned from discussions with fleet maintenance managers, is lights placed on vehicles that exposes them to physical damage.
“Today’s modern fleet main managers are looking for continuous improvements and are looking at data for the most frequent occurrences that lead to waste,” VanRiper said.
The data point to placing lights “into areas where they are not going to get knocked off by a tree limb,” he said. That’s the emphasis for Generation 2 and Generation 3 LED products. It’s critical to get less physical damage.”