Although LEDs are fairly new to the truck and transit industries, they have been used in the automotive industry for several years, mainly in instrument panels. The more electronic control that is used in a vehicle, the greater the need for low-voltage systems.
In the transit industry, coach charging systems are used to capacity, and the introduction of LEDs in instrument panels, indicator panels (light bars), tail lights, side marker lights, multiplexing modules and interior floor lighting greatly reduces the load on the charging system.
The benefits of LEDs
LEDs are light emitting diodes. These are semiconductor lamps that operate on very low voltage and generate very little heat. Most LEDs operate on 10 to 20 milliamperes of current. Since one milliampere is one-thousandth of an ampere, there is almost no heat generated by the LED. At this low amperage, the life of the LED is much greater than its incandescent counterpart.
Side marker lights on transit coaches have eight LEDs with diodes and resistors mounted on a circuit board. Stop and tail lights have 61 LEDs with diodes and resistors mounted on a circuit board. The circuit boards are configured in a parallel design so that if any LED fails, the remaining lights on the board will still work. If they were configured in a series design and any LED failed, all LEDs after the failed LED would not work.
LEDs also have the benefit of nearly instantaneous response, especially helpful with brake lights. This can reduce the number of accidents in which the bus is rear-ended because it gives a trailing motorist a fraction of a second more time to respond to the brake lights.
Although some LED lighting can be repaired, lights used on the outside of the coach cannot. These lights are mounted in a waterproof case that is destroyed when taking circuit boards out. I researched this myself by taking one apart and repairing it. The light worked, but I could not waterproof the case, and we all know what water and moisture do to electronic equipment. It’s cheaper and makes more sense to replace burned out lights with new ones.
No problems reported
At the Transit Authority of River City in Louisville, Ky., we use LED lighting manufactured by Dialight Corp. They are installed at the Gillig Corp. when the coaches are built. We now have LED lighting on 152 coaches and have had no problems with them. It probably costs a little more initially to have the LED lighting installed, but the rewards far outweigh the cost.
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