Trailer Talk

Jackknifes Happen Often on Dry Roads, Too

This all occurred in just a second or two, though it took several seconds for the rig to stop, the trailer jammed against a corner of the tractor’s sleeper.

March 13, 2017

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It appears the driver hit the binders and the tractor's brakes seem to be sticking, pulling the rig to the left. Screenshots from ABC newscast. 
It appears the driver hit the binders and the tractor's brakes seem to be sticking, pulling the rig to the left. Screenshots from ABC newscast.

Forgive me if I devote too many of these blogs to jackknifing, but ‘tis the season of slick pavement when a lot of such accidents occur. They are dangerous to the errant rig’s driver and to other truck drivers and motorists nearby and can cause a lot of expensive damage.

But how about a jackknife on dry pavement? Here are some images from a TV newscast of a tractor and dump trailer suddenly going out of control, bending to port (as a sailor might say), and skidding across several lanes on a freeway and blocking them as it comes to a jarring halt. What the blazes could cause that?

The very short news report didn’t include the accident’s whereabouts, and I searched on Google and YouTube but couldn’t find it. What I did find in short order were a lot of recent jackknifing incidents, almost from coast-to-coast. Quite a few were on dry pavement, some resulted in injuries, and all caused traffic tie-ups that teed off a lot of people.

Now at an acute angle, the rig continues skidding across several lanes on this freeway, location unknown. 
Now at an acute angle, the rig continues skidding across several lanes on this freeway, location unknown.

I studied the short video and these pics several times and determined that the driver apparently hit the binders hard when he saw traffic ahead slow down. It appears that the brakes on his rig grabbed, the wheels locked, and the tires began skating across the asphalt.

Anti-lock braking systems are supposed to keep brakes from locking, but this time didn’t. Why might that be? I invite experts and experienced drivers to offer opinions in the comment section below. Meanwhile, here’s what I think:

The tractor's brakes were out of adjustment, and/or air valves were sticking, so the brakes didn’t release when told to by the ABS. It’s also possible that the tractor was built before ABS was required (March 1, 1997) and simply didn’t have it. As I said in a previous blog, a skidding wheel wants to lead, and they did in this case, dragging the tractor to the left. The trailer followed along.

The rig lurches to a stop with probable damage to the tractor's sleeper and who knows what else. No word of any injuries. 
The rig lurches to a stop with probable damage to the tractor's sleeper and who knows what else. No word of any injuries.

This all occurred in just a few seconds, from the spinout until the rig stopped, the trailer jamming against a corner of the tractor’s sleeper. As victims of accidents always say, “It happened so fast….” It sure does. When’s the last time you had your brake system checked?

Comments

  1. 1. Keith Johnson [ March 14, 2017 @ 04:31AM ]

    Dry weather jack knife on I-75 in Dayton Sunday morning.

  2. 2. Dennis O Taylor [ March 14, 2017 @ 09:04AM ]

    Is it possible to tell if the trailer was loaded or not? I suspect an empty or lightly loaded trailer. In that case, weight transfer (during braking) to the front axle is primarily from the tractor itself, not so much from the trailer. If one front brake sticks (left, in this case) or is faster to act than the other, there will be a force causing the tractor to rotate counter-clockwise. Assuming the momentum prior to brake application is along the longitudinal axis of the truck, there will be rotation in the direction shown.

  3. 3. Kirk Ziegler [ April 06, 2017 @ 01:30AM ]

    great tips for supercars owners! http://www.247collisioncare.com/

  4. 4. M Mestar [ May 20, 2017 @ 10:43AM ]

    Jackknifing starts as a skid, so do your best to avoid skidding. If, however, your vehicle starts to skid, take your foot off the brake immediately and correct the skid as you would with a rigid vehicle . If it isn't corrected, it will be aggravated by the trailer pushing from behind and the vehicle will jackknife.
    http://www.ogdentrucktrailer.com

 

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Author Bio

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Tom Berg

Senior Contributing Editor

Journalist since 1965, truck writer and editor since 1978. CDL-qualified; conducts road tests on new heavy-, medium- and light-duty tractors and trucks. Specializes in vocational and hybrid vehicles.

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