The American firm Truck-Lite have released the first full family of rear lamps performing primary stop/tail and direction indicator functions with just a single LED emitter.
The modular lamps come in the 4-inch (100 mm) round form factor, the most popular of the four standardised size formats used almost universally by the North American heavy truck, trailer, and bus industries. Fresnel optics are used to spread and distribute the light through the required angles.
Although the new lamps come in a format most popular in the NAFTA market, they are not SAE or DOT certified for use in the USA. Rather, they are type-approved according to international ECE regulations. The range also includes a new 2-emitter ECE rear fog lamp. Minimum permissible intensities are higher for the stop and turn functions under SAE regulations, suggesting DOT versions of these lamps may be released after the next jump in emitter output.