Are there any " Warning signs" for A Jack knife?

Have you ever heard of driving by the seat of your pants. And if there's more trailers good luck with that. yeah it's kind of like that.

 

I've seen signs for a roll over, slippery road, lanes merging... etc..

Never one for a jack knife.

Is that the next thing to come?
Some politician decides that more warning signs are needed, and so we have to take our eyes off the road once again for another sign.

WARNING! Jack knife possible if conditions are slippery and you are going too fast.


And no big deal.
It will only cost 13 billion dollars to spray those signs all over everywhere.

 

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At Pumpkin they had us do simulator training for trailer losing traction on ice and they taught us clutch in, foot off the accelerator, and steer into the skid, then when the trailer swings back steer that way and keep repeating until it straightens out.

 

That's correct.. the issue is that only works with room to the front.. while careening towards something you don't want to run into is the problem. Releasing the brakes (accelerating) is the way to fix it.. drivers rarely have that option when these start to go sideways..

 

The key to avoiding a jack knife is to avoid it all together. Understanding what causes a jack knife and taking the appropriate action(s) will keep you out of the situation. A jack knife occurs when the towing vehicle begins to skid. Hauling an empty trailer or even a light load can increase the risk of jack knife. Spread braking and decelerating over as long of a distance as possible. Avoid braking or slowing down on a curve. If you need to take avoiding action do not brake and swerve at the same time. If a jack knife does begin take your foot off the brake immediately and correct as if driving a rigid vehicle.

 

Coasting is your friend.

The closest I came to a jack knife was westbound on I-20 just west of Dallas a couple of winters ago. I was watching the ambient air temperature like a hawk as it dropped below freezing, then started to rain. Just before getting to a planned stop to get coffee I came up an overpass and suddenly had about a one foot yaw to the left.

I immediately got off the throttle and steered right and it snapped back in line. Mind you I was very gentle on the throttle coming up the rise, but it still initiated a yaw.

I pulled in to the truck stop right after that to see that the ice storm that was centered in Amarillo had dropped down to I-20, directly in my route. Because it was light rain I opted to continue cautiously. That night turned into a memorable experience. I-20 soon became a challenge, with freezing rain turning into a full blown blizzard with lightening. I engaged the interaxle differential lock and made it to Pecos, out of the storm and my teammate took over in the morning.

The most important thing in my book is to keep an EASY foot on the throttle and hold the steering wheel like you are holding a wounded sparrow. Every input needs to be nice and easy. If you turn off the music and concentrate on what you feel from the wheel and the seat you can tell if it is getting "greasy".

Remember, COASTING IS YOUR FRIEND. If you feel any issues with lack of ability to turn or the start if a yaw, then GET OFF THE THROTTLE.

Stay below 50% boost on your turbo (if you have a boost gauge) or at about 50 of maximum horsepower. That translates into about 1/4 to 1/3 into the throttle, depending on your truck. Bleed off speed going uphill, feathering the throttle and let it coast down hills.

Coasting is your friend.

 

Not really, past the 45 deg. point. Hit the hand valve and same time slightly eccelerate. Did it one time, LUCKY.

 

The idiocy of desk jockeys are now speccing fleet trucks without trolley brakes. I also drove trucks for Swift where the trolley brake would do nothing and then suddenly jump to 20-25 psi instantly. I LIKE a proper trolley brake, especially if it is on the steering column. If it is up on the dash and grabs hard I forgot about it.

 

Yes, I remember that technique very well and I used to promote that one myself in the 80's but let me tell you why I don't anymore. That maneuver may work provided that the conditions are dry enough. The problem with that theory is that if it were dry enough, there wouldn't have been a problem to begin with. If you attempt that maneuver and your trailer wheels and/or tractor wheels are still on ice, it is going to compound the problem. I have come to the conclusion that the best maneuver is paying attention and not letting it happen to begin with. However, the most important element in paying attention is keeping the noise(radio, talking on CB, phone etc.) down and paying attention to your RPM's with your ears. And don't run at the top of the governor. It is also requires considerably reducing your speed and increasing your following distance. If you are paying attention you will be able to recognize when you have broke traction. Immediately releasing the accelerator and steering in the direction of your tandems will prevent a jackknife every time. If your tandems swing right, steer right to come out of it and than back as it straightens out. If you have to keep hitting your brakes, you're following too close. Stay off Cruise Control when icy too.