Sooner or later, a vehicle's incandescent light bulbs will burn out and will need to be replaced. In general, it's still best to replace like with like when it comes to bulbs. However, there are options that allow a fleet manager to upgrade original equipment exterior lighting on tractors and trailers. Nowadays, few will dispute the benefits of including light-emitting diodes (LEDs) when spec'ing new equipment. Tim Gilbert, corporate director heavy-duty fleet and OEM sales, Peterson, says fleets can extend fleet life and reduce maintenance costs with LEDS. All their lighting uses internal-return ground systems, instead of frame-rail grounding. It used to be that for replacement headlamps, the choice was dictated by whether your truck had round or rectangular sealed beams in dual high/low beam or separate high/low quad configuration. Halogen sealed beams, once a premium option, have become the standard for this type because they are brighter.