It isn't universal yet but if you look at the top of the cabs of some tractors, you'll see a white plastic dome. A lot of UPS trucks have these too. This is a GPS tracking antenna. The trucking industry is getting tired of higher insurance rates brought on by the few hotrodder truckers. There are several companies out there that trucking companies contract with that get electronic GPS reports on where the trucks have been, where they're going and how fast. These companies usually give a monthly report on each truck and, if requested by the trucking company, more often or immediately if the trucker is a chronic speeder or makes an unscheduled stop. This service, in most cases, qualify the company for lower insurance rates if all or most of the drivers have clean driving records to begin with. Back in the late 1970's, I worked for a concrete block / ready mix company in Florida that was owned by one man. ONE VERY MISERLY OLD MAN. If you drove a block or mixer truck, you had to have a clean, "class A chauffeur's license". This was before CDL's. He would pull your driving report 4 times a year. If you got a ticket, even in your own car, if you were going to fight it, he would put you in the scale house weighing ingredients or working in the block plant until your court date. If you won, you got your truck back. If you lost, or you just paid the ticket ie. pled guilty, you're fired. If he got your report and there was a ticket or an "at fault" accident on it that you didn't report to the plant manager, you're fired. He did this to keep his truck insurance rates low. I'd bet that his insurance company loved him for it.

Once you are moving at speed downhill, changing gears isn't an option. The key is to be in a lower gear at the top of the hill. You'll burn out your brakes trying to slow down as well.

"Even experienced truck drivers occasionally "miss a gear" while downshifting on down grades leaving them stuck in neutral and having to depend solely on their brakes for speed control." That's why they're supposed to be in the lower gear BEFORE they start going down the hill. That rig weighs over 78,000 lbs; any trucker downshifting on the down grade with a load of paper rolls shouldn't be a trucker to begin with. He had at least 5 miles of signs warning him of the steep grade ahead so he pretty much doesn't have any excuses. The TDS outburst at the end of your wall of text was pathetic.

@@Mike_Wilson_KJV My point was that even people like YOU and me are fallible. As for your 5 miles of signs, that's bullsh,it. If you come north on I-79 in West Virginia between exits 99 and 105, you find ONE sign less than a mile from the multiple sharp swerves in the road telling truck drivers that their speed limit drops from 70 to 55 MPH due to a rollover hazard. This is a federal road. If you go east on state road 33 just outside of Elkins West Virginia, you will find the ONLY "warning 7% grade next..." however many miles ON THE WAY DOWN THE HILL. As for my wall of text, I could have shortened it to where you and I would understand it but to other people in the world who don't know the intricacies and differences between driving a 2,500 pound passenger car and an 80,000 pound truck, my essay wouldn't have made any sense to them. I was writing for them, not you. I find your self centered, know it all attitude pathetic. If it's too long and difficult for you to read, DON'T READ IT!!! No one put a gun to your head.

ok

UHHH, they CAN'T stay in low gear. Truck diesel engines are governed / limited to about 3,600 RPM. If they stayed in low gear on the way down a hill: 1) You would be complaining that it took you 2 weeks to drive down a shallow hill behind a truck driving 2 MPH, (it's engine's safe top speed in low gear.) 2) If you were to pass a truck driving in low gear going down a 10% grade out west somewhere, you might find that you picked up a 10 pound piston or a 100+ pound chunk of his crankshaft through your passenger window when his engine exploded as you cruised on by. and 3) if you survived the first two scenarios, your local store shelves would look like Covid came back with a vengeance with chronically empty shelves and higher prices due to increased diesel fuel usage. A new idea came out around the 1980's called J.I.T. shipping or J.I.T. transport. J.I.T. stands for Just In Time. The idea is if stores keep a lot of extra stock in their back room, That's money not earning interest in the bank or sitting on already full shelves waiting to harvest your wallet. When stock rooms and out the door sales began to get computerized, corporations began to hire analysts to come in, look at sales data and patterns and devise a way to order close to just enough stock to fill their shelves and figure out when to reorder just before they ran out so that the truck would show up JUST IN TIME to restock the shelves. When you go to the store and find that they are out of something that you wanted, either there was an unexpectedly high demand for that item, the supplier ran out of it in their warehouse or somebody in the ordering department screwed up and ordered it too late. Truck drivers seem to ne in a hurry because they are pinched between the customer's scheduled delivery time and date at their destination and the department of transportation law that says they can only drive 10 hours and MUST stop to take an 8 hour break, hopefully to get some sleep. Truck drivers, by federal law, must keep a log book with such information as what time and date that they entered a state and when they left, if applicable, what mile marker they passed at what time and date several times in a 10 hour shift, what speed they were driving, what time and date if they stopped for fuel, a meal, a restroom or an 8 hour break. It must be detailed enough so that if a law enforcement officer or DOT inspector pulls them over, they can check the log against how many miles you drove, calculate the speed that you drove and if and when you took your federally mandated 8 hour break while doing all this on a calculator. This is why you see a bunch of trucks parked at interstate truck travel centers or at interstate rest stops. They aren't goofing off or being lazy. Most of them are complying with federal law. If their log is missing information or if they even get a whiff that the trucker had faked something, It can cost them major bucks and potentially, their CDL, (Commercial Drivers License), which also means that they are out of a job, in most cases, and they can't drive their personal car to work at McDonalds.

...the fact that are parts getting sold and it gets found out when it's too late... Very true. Even brand name parts have occasional defects. Back in the middle 1970's, I took a 2 year diesel mechanics course. If a business owner or you, as an owner / operator had the time for your truck to be down for several weeks, you could bring it to the school and have it repaired labor free with discounted name brand parts by students under the supervision of experienced teacher / mechanics. This was just about the time when new trucks were starting to convert over to disk brakes. We had an older dump truck come in once that had the new asbestos brake lining fall off the metal shoe. This was a new Bendix part. Luckily, it happened at city speeds and, when it fell off, it jammed between the metal shoe and brake drum bringing the truck to an abrupt halt after skidding that one dual for some feet.