Standard No. 108 Definitions

Aiming plane means a plane defined by the surface of the three aiming pads on the lens. Aiming reference plane means a plane which is perpendicular to the longitudinal axis of the vehicle and tangent to the forward most aiming pad on the headlamp. Aiming screws are the horizontal and vertical adjusting screws with self-locking features used to aim and retain a headlamp unit in the proper position. Axis of reference means the characteristic axis of the lamp for use as the direction of reference (H = 0°, V = 0°) for angles of field for photometric measurements and for installing the lamp on the vehicle. Backup lamp means a lamp or lamps which illuminate the road to the rear of a vehicle and provide a warning signal to pedestrians and other drivers when the vehicle is backing up or is about to back up. Beam contributor means an indivisible optical assembly including a lens, reflector, and light source, that is part of an integral beam head lighting system and contributes only a portion of a headlamp beam. Cargo lamp is a lamp that is mounted on a multipurpose passenger vehicle, truck, or bus for the purpose of providing illumination to load or unload cargo. Clearance lamps are lamps which show to the front or rear of the vehicle, mounted on the permanent structure of the vehicle as near as practicable to the upper left and right extreme edges to indicate the overall width and height of the vehicle. Coated materials means a material which has a coating applied to the surface of the finished sample to impart some protective properties. Coating identification means a mark of the manufacturer's name, formulation designation number, and recommendations for application. Color Fundamental definitions of color are expressed by Chromaticity Coordinates according to the CIE 1931 Standard Colorimetric System, as described in the CIE 1931 Chromaticity Diagram (incorporated by reference, see § 571.5). Color bleeding means the migration of color out of a plastic part onto the surrounding surface. Combination clearance and side marker lamps are single lamps which simultaneously fulfill the requirements of clearance and side marker lamps. Combination headlamp means a headlamp that is a combination of two different headlamp types chosen from a type F sealed beam headlamp, an integral beam headlamp, or a replaceable bulb headlamp. Cracking means a separation of adjacent sections of a plastic material with penetration into the specimen. Crazing means a network of apparent fine cracks on or beneath the surface of materials. Cutoff means a generally horizontal, visual/optical aiming cue in the lower beam that marks a separation between areas of higher and lower luminance. Daytime running lamps (DRLs) are steady burning lamps that are used to improve the conspicuity of a vehicle from the front and front sides when the regular headlamps are not required for driving. Delamination means a separation of the layers of a material including coatings. Design voltage means the voltage used for design purposes. Direct reading indicator means a device that is mounted in its entirety on a headlamp or headlamp aiming or headlamp mounting equipment, is part of a VHAD, and provides information about headlamp aim in an analog or digital format. Effective light-emitting surface means that portion of a lamp that directs light to the photometric test pattern, and does not include transparent lenses, mounting hole bosses, reflex reflector area, beads or rims that may glow or produce small areas of increased intensity as a result of uncontrolled light from an area of 1/2 ° radius around a test point. Effective projected luminous lens area means the area of the orthogonal projection of the effective light-emitting surface of a lamp on a plane perpendicular to a defined direction relative to the axis of reference. Unless otherwise specified, the direction is coincident with the axis of reference. Exposed means material used in lenses or optical devices exposed to direct sunlight as installed on the vehicle. Filament means that part of the light source or light emitting element(s), such as a resistive element, the excited portion of a specific mixture of gases under pressure, or any part of other energy conversion sources, that generates radiant energy which can be seen. Flash means a cycle of activation and deactivation of a lamp by automatic means continuing until stopped either automatically or manually. Fully opened means the position of the headlamp concealment device in which the headlamp is in the design open operating position. H-V axis means the line from the center of the principal filament of a lamp to the intersection of the horizontal (H) and vertical (V) lines of a photometric test screen. Haze means the cloudy or turbid appearance of an otherwise transparent specimen caused by light scattered from within the specimen or from its surface. Headlamp means a lighting device providing an upper and/or a lower beam used for providing illumination forward of the vehicle. Headlamp concealment device means a device, with its operating system and components, that provides concealment of the headlamp when it is not in use, including a movable headlamp cover and a headlamp that displaces for concealment purposes. Headlamp mechanical axis means the line formed by the intersection of a horizontal and a vertical plane through the light source parallel to the longitudinal axis of the vehicle. If the mechanical axis of the headlamp is not at the geometric center of the lens, then the location will be indicated by the manufacturer on the headlamp. Headlamp test fixture means a device designed to support a headlamp or headlamp assembly in the test position specified in the laboratory tests and whose mounting hardware and components are those necessary to operate the headlamp as installed in a motor vehicle. High-mounted stop lamp means a lamp mounted high and possibly forward of the tail, stop, and rear turn signal lamps intended to give a steady stop warning through intervening vehicles to operators of following vehicles. Identification lamps are lamps used in groups of three, in a horizontal row, which show to the front or rear or both, having lamp centers spaced not less than [6 in] 15.2 mm nor more than [12 in] 30.4 mm apart, mounted on the permanent structure as near as practicable to the vertical center-line and the top of the vehicle to identify certain types of vehicles. Integral beam headlamp means a headlamp (other than a standardized sealed beam headlamp designed to conform to paragraph S10.13 or a replaceable bulb headlamp designed to conform to paragraph S10.15) comprising an integral and indivisible optical assembly including lens, reflector, and light source, except that a headlamp conforming to paragraph S10.18.8 or paragraph S10.18.9 may have a lens designed to be replaceable. License plate lamp means a lamp used to illuminate the license plate on the rear of a vehicle. Lower beam means a beam intended to illuminate the road and its environs ahead of the vehicle when meeting or closely following another vehicle. Material means the type and grade of plastics, composition, and manufacturer's designation number and color. Mechanically aimable headlamp means a headlamp having three pads on the lens, forming an aiming plane used for laboratory photometric testing and for adjusting and inspecting the aim of the headlamp when installed on the vehicle. Motor driven cycle means every motorcycle, including every motor scooter, with a motor which produces not more than 5 horsepower, and every bicycle with motor attached. Motorcycle or motor driven cycle headlamp means a major lighting device used to produce general illumination ahead of the vehicle. Mounting ring means the adjustable ring upon which a sealed beam unit is mounted. Mounting ring (type F sealed beam) means the adjustable ring upon which a sealed beam unit is mounted and which forces the sealed beam unit to seat against the aiming ring when assembled into a sealed beam assembly. Multiple compartment lamp means a device which gives its indication by two or more separately lighted areas which are joined by one or more common parts, such as a housing or lens. Multiple lamp arrangement means an array of two or more separate lamps on each side of the vehicle which operate together to give a signal. Optically combined means a lamp having a single or two filament light source or two or more separate light sources that operate in different ways, and has its optically functional lens area wholly or partially common to two or more lamp functions. Overall width means the nominal design dimension of the widest part of the vehicle, exclusive of signal lamps, marker lamps, outside rearview mirrors, flexible fender extensions, mud flaps, and outside door handles determined with doors and windows closed, and the wheels in the straight-ahead position. Running boards may also be excluded from the determination of overall width if they do not extend beyond the width as determined by the other items excluded by this definition. Parking lamps are lamps on both the left and right of the vehicle which show to the front and are intended to mark the vehicle when parked or serve as a reserve front position indicating system in the event of headlamp failure. Protected means material used in inner lenses for optical devices where such lenses are protected from exposure to the sun by an outer lens made of materials meeting the requirements for exposed plastics. Rated voltage means the nominal circuit or vehicle electrical system voltage classification. Reflex reflectors are devices used on vehicles to give an indication to approaching drivers using reflected light from the lamps of the approaching vehicle. Remote reading indicator means a device that is not mounted in its entirety on a headlamp or headlamp aiming or headlamp mounting equipment, but otherwise meets the definition of a direct reading indicator. Replaceable bulb headlamp means a headlamp comprising a bonded lens and reflector assembly and one or two replaceable light sources, except that a headlamp conforming to paragraph S10.18.8 or paragraph S10.18.9 may have a lens designed to be replaceable. Replaceable light source means an assembly of a capsule, base, and terminals that is designed to conform to the requirements of appendix A or appendix B of 49 CFR part 564 Replaceable Light Source Information of this Chapter. Retaining ring means the clamping ring that holds a sealed beam unit against a mounting ring. Retaining ring (type F sealed beam) means the clamping ring that holds a sealed beam unit against a mounting ring, and that provides an interface between the unit's aiming/seating pads and the headlamp aimer adapter (locating plate). School bus signal lamps are alternately flashing lamps mounted horizontally both front and rear, intended to identify a vehicle as a school bus and to inform other users of the highway that such vehicle is stopped on the highway to take on or discharge school children. Sealed beam headlamp means an integral and indivisible optical assembly including the light source with “SEALED BEAM” molded in the lens. Sealed beam headlamp assembly means a major lighting assembly which includes one or more sealed beam units used to provide general illumination ahead of the vehicle. Seasoning means the process of energizing the filament of a headlamp at design voltage for a period of time equal to 1% of design life, or other equivalent method. Semiautomatic headlamp beam switching device is one which provides either automatic or manual control of beam switching at the option of the driver. When the control is automatic the headlamps switch from the upper beam to the lower beam when illuminated by the headlamps on an approaching vehicle and switch back to the upper beam when the road ahead is dark. When the control is manual, the driver may obtain either beam manually regardless of the conditions ahead of the vehicle. Side marker lamps are lamps which show to the side of the vehicle, mounted on the permanent structure of the vehicle as near as practicable to the front and rear edges to indicate the overall length of the vehicle. Additional lamps may also be mounted at intermediate locations on the sides of the vehicle. Stop lamps are lamps giving a steady light to the rear of a vehicle to indicate a vehicle is stopping or diminishing speed by braking. Tail-lamps are steady burning low intensity lamps used to designate the rear of a vehicle.