The regulatory lettering that has to be on a commercial vehicle before it turns a wheel: USDOT and MC numbers, CVOR and NSC identifiers, carrier name, weight ratings, and the fleet unit numbers that let a dispatcher, a yard hand and an inspector all name the same truck.

Two materials, chosen for two different jobs. 3M-IJ175 is the everyday choice for cab-door lettering — durable exterior vinyl that survives washes, weather and years of sun on a door skin. Reflective vinyl is there for unit numbers that have to be read at night, on a trailer roof or side, in a dark yard, or wherever a fleet policy or customer specification calls for retroreflective identification.

The rules come from your jurisdiction and your operating authority, not from us. The common requirement is that the marking be permanently affixed, in a colour that contrasts sharply with the background, and legible from fifty feet in daylight — which in practice means around two inches of character height, though several agencies specify their own minimums and placements. Check yours and tell us the height you need; we will set it exactly.

Send the exact strings you want — spelling, spacing, punctuation, leading zeros and all — and check the proof carefully, because a transposed digit on a DOT number is the kind of error that surfaces at a roadside inspection rather than in the shop. We set each door as a single unit so that carrier name, number and weight lines stay in correct relationship to one another.

You receive weeded lettering pre-mounted on transfer tape, one piece per door or panel, so a whole block goes on square and aligned in a single application. Contour cut trims to the character outlines with no visible carrier rectangle. Lamination is worth adding on tractors and trailers that see winter salt and daily wash bays.

Wipe the door with isopropyl alcohol before applying — road film and wax are the usual reason lettering releases at the edges. Apply above 10°C on a dry surface.