Understanding lighting requirements for work trucks

From an NTEA member As a work truck upfitter installing a variety of truck bodies, we struggle to make sure we have all the required lights and reflectors on the completed vehicles. Can you help us understand the lighting requirements we must meet? Work truck upfitters building from an incomplete vehicle such as a cab chassis or cutaway are required to ensure the completed vehicle meets all applicable Federal Motor Vehicle Safety Standards (FMVSS) through the multi-stage vehicle certification process. Many upfitters encounter challenges when implementing FMVSS 108 lighting requirements. Body manufacturers will incorporate lighting into their truck bodies, but that lighting doesn’t typically account for additional equipment or the incomplete chassis onto which the body is mounted. These instances may require relocation of the supplied lighting or the addition of auxiliary lighting in order to meet requirements. Installers of required lighting on a new motor vehicle should understand and meet two main compliance criteria. Each lamp has photometric performance requirements (how intense a lamp needs to be and at what distances) and location — including visibility — requirements (proper placement on the vehicle and range of viewing angles in which the lamp must be seen). Within lighting compliance, photometric requirements are usually handled by lighting manufacturers because they design and construct lamps to meet the colors, intensity levels and other performance/construction related to photometric requirements. The upfitter or final-stage manufacturer is ultimately responsible for ensuring compliance with all of the lighting requirements — but having the performance requirements already built into the lamps helps the upfitter select the proper lamp and reflector for a specific lighting function, such as a stop or clearance lamp. The upfitter is also responsible for making sure required lamps are correctly placed on the vehicle, function properly and meet visibility requirements in those locations. When ensuring the completed vehicle meets FMVSS 108, the upfitter should review all lights and their required function. Since each lamp must meet a specific FMVSS for performance and durability, the lamp lens is stamped or embossed DOT to identify it meets specific FMVSS 108 requirements. Additionally, the lamp manufacturer can code the lamp identification requirements on the lens. More coding designations are found in SAE Recommended Practice J759, and the lamp manufacturer can use this coding system to indicate the functions for which they are suitable (stop lamp, tail lamp, etc.). By using these codes, an upfitter can determine which SAE lighting standard a lamp will meet and, in turn, if it will be capable of meeting the requirements of FMVSS 108 for a particular lamp function. The identification codes consist of a series of numbers and letters, and may be permanently marked on the lens or body of the light. Upfitters must also correctly position the light based on FMVSS 108 requirements. NTEA members can access an Interactive Lighting Guide for help in determining position and proper function of required lighting. If the truck body, equipment and/or accessories obscure the lighting and prevent the vehicle from meeting visibility requirements of FMVSS 108, the light must be repositioned or an auxiliary light needs to be installed. For example, liftgate installations often require auxiliary lights or relocation of existing lights because the added liftgate often covers the lighting installed by the body manufacturer. FMVSS 108 also includes functional requirements, such as the speed at which a turn signal flashes. The chassis OEM programs the flasher module to meet these requirements based on expected voltage draw. Some upfitters use turn signal lamps that will not meet the expected voltage draw, and consequently, the turn signals flash rapidly. The final-stage manufacturer must correct this rapid flash issue in order to properly certify the vehicle. Meeting lighting requirements on a work truck may pose some challenges, but there are tools available to help upfitters meet their certification obligations, including application guides from lighting suppliers, wiring diagram and body builder manuals from chassis OEMs, and NTEA and National Highway Traffic Safety Administration lighting charts.

Understanding lighting requirements for work trucks

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