There’s dropping trailers, as in hook-and-drop operations, and there’s dropping a trailer, as in whoops! It never occurred to me that the second kind – trailers coming loose from fifth wheels and dropping onto their landing gear or down on their noses – was a problem until two suppliers introduced products to help avoid it.

A few weeks ago SAF-Holland demonstrated one, and late last week Purkeys Fleet Electric announced another. Both use special LED lights that shine onto a fifth wheel’s jaws so drivers can see whether they’ve properly grabbed onto the trailer’s king pin.

People at those companies relate that, based on conversations with fleet managers, trailers are accidently dropped way more often than many of us realize. A few major fleets said they each see it happen hundreds of times a year. Usually the incidents are minor and no one’s hurt. But it's embarrassing, and rectifying things takes time and sometimes money (as in calling a wrecker to lift a trailer’s nose).

Sometimes it’s the result of a prank – someone will pull the release handle and laugh as the driver pulls away and there goes the trailer, down on its knees or, if the landing gear collapses, on its nose. One driver told me a Teamster striker did this as my friend was talking his way through a picket line. The landing gear held, but, "It took me four hours to crank the trailer back up," he said.

Occasionally a trailer comes loose on a highway, creating a dangerous situation for traffic behind. People have been injured and killed when slamming into dropped trailers. Some people might think manufacturers are to blame, but they design and build fifth wheels and upper couplers (including king pins) that meet stringent standards.

Unless corrosion is a factor, we’ve got to point at drivers who haven’t exercised due care. Because like most accidents, human error is the cause.

Over the years I’ve done some hooking-and-dropping (the intentional kind) and never considered it a problem, as long as the height of the fifth wheel and the trailer’s nose were the same. Sometimes they weren’t, and it took dumping of the tractor’s air-bag suspension or some vigorous cranking of the landing gear to get a proper match. (Another product, from Hadley, helps with that.)

Of course I always did a visual inspection, checking the fifth wheel’s release handle to see that it had snapped back inward, indicating the jaws had locked shut. Then I crab-walked under the trailer to peer into the fifth wheel to see that the jaws were set around the king pin. And I did a tug test soon after moving away from the parking place, applying the trailer brakes with the “trolley” handle to be sure the coupling was tight. Partly from precaution and partly from luck, I never had a “whoops” incident.

Videos of proper coupling and uncoupling procedures from manufacturers, drivers, fleets and schools are posted on YouTube. So anyone with access to the Internet ought to know what he or she is doing. And some of the latest products make it a little easier.