Why Some Semi-Truck Trailers Have Quilted Rear Doors

If you've driven behind certain semi-trucks on the highway, you might've noticed that the rear door of the truck's trailer has a distinctive, diamond-shaped pattern covering it. This pattern resembles the stitched squares of a large quilt, giving the doors a bit of stylish personality to contrast with the hard angles of the rest of the trailer's body and surfaces. You see this most frequently on refrigerated trucks, or "reefers," which may also have a little door on the backs of their trailers. Of course, style isn't the only reason a truck trailer might have this distinctive pattern.

Covering the back of a truck trailer with those diamond shapes affords the doors a handful of small, yet practical benefits. These benefits include a greater resistance to the corrosion that straight metal doors are vulnerable to, greater ease for the driver to clean any gunk off the back, and perhaps most importantly, reduced glare to other motorists on a sunny day. If you were even able to make out that diamond pattern on the trailer's door at all, you have the quilted pattern itself to thank for it.

A normal semi-truck trailer's rear door is a solid slab of metal, often with a somewhat reflective surface. Consider this: If it were a particularly hot and sunny day out, the light of the sun is going to beam right down onto that reflective surface and bounce off. If you happened to be in your own car, driving right behind that trailer, that solid wall of reflected light is going to bounce right into your face and eyes. Even if you weren't completely blinded, your vision would be more than sufficiently impaired to endanger you and anyone driving around you. Considering how slow semi-trucks are on the highway, you're not getting out of that heat blast easily.

This is one of the main reasons a semi-truck trailer may employ quilted rear doors — by adding some texture to the trailer's doors in the form of that diamond pattern, any light the doors receive will be broken up and scattered about instead of being reflected in a single, large blob. You might still get an errant beam in your face if you're driving behind the truck, but you could just move your head a bit to get out of the way.

In addition to glare reduction, trucking brands like Utility Trailer list several other benefits to diamond-patterned trailer doors, particularly cleanliness and corrosion resistance. The grooves of the pattern make it easier to clean assorted dirt and debris off the trailer door, while the pattern itself makes the door more resistant to corrosion from rain or road salt. Corrosion is a scourge on any vehicle, so any trick you can use to protect your vehicle from rust is vital.