Safety is a overused, worn out, road hard and put up wet word or concept. Toss it.
What do you have left? A good Jacobs Braking system is every bit as vailible as a engine that will give you 2150 ungoverned at relined in top gear. A GOOD engine is a ASSET to trucking due to the weights involved.
My Jacobs two switches are always on. Usually Cruise on and Jacobs stage three. (Maybe once or twice in my lifetime I mess with stage one or two which really does not help) All or nothing.
I am the one who decides what the engine is to do in the realm of speed control and mountain driving which is the one thing I am very good at. I once was afraid deathly of mountains but now am considering myself a God when it comes to this sort of thing, any weather, any season it does not matter. Unless it is really bad then it’s probably to take advantage of that safety thing by finding a safe spot with food, communications and fuel to park at for the duration.
I refuse to drive a truck without a Jacobs. However I still remember what I will have to do if I lose the Jacobs at any time to a fuse short or some other issue too deep to deal with it while rolling down the mountain. That tractor trailer will be under control.
There is no such thing as promote fuel economy. You have 335 gallons worth in two tanks out of 347 total volume and you should be able to use that fuel to get you 1650 minimum number miles before fueling again in the winter (At half tanks) due to a abundance of caution. I usually get 2100, but NOT always. I always have a plan to fuel after 1650 miles anywhere in the USA and or Canada.
If you want fuel economy, buy one egg. Crusable. Put that egg between your foot and fuel pedal. Now we will see about that 10 miles per gallon, or even beyond. (Don’t. This is strictly a hyperbole and I will not be responsible for the shorted Binary counting chip under the fuel pedal among other problems)
The Jacobs situation depends on gravity and traction. If I can use it, it’s coming on. If I don’t need to use it? It will be a while. I am one of those old schooled trained drivers come down through all the gears when slowing from 70 to 2nd gear towards a light on a highway off ramp for example. It gets pretty busy in there. But since the 18 wheeler is by extension a aspect of my will and decision making, the actual doing is not a drain at all.