Steep Downhill and you need to downshift

Another forum member posted a link to this video, which has made for a lot of discussion with my brother and I (team drivers).

http://www.youtube.com/watch?v=Tx0jXI2VyJ8

It is likely that the trainee that was driving the truck was in a gear too high to allow the jake brake to control speed effectively going down the steep grade. In turn that meant he had to use the service brakes too much to control speed (and likely meant he was worried about over heating the brakes or losing air pressure from over use). His final fatal mistake was applying brakes when going into the turn, something that you should never do! Both the trainee and the trainer were killed in this roll over accident.

My question to experienced drivers is what do you do when you have entered a sustained down hill grade and realize you need to down shift? How do you handle that situation?

My solution is to apply the service brakes until my rpm's are so low they are almost lugging the current gear, then go for a downshift. This means I don't need to spend a lot of time on the throttle to bring the rpm's up to grab the gear. A few weeks ago I was driving from Joshua Tree south on the 62 and saw the signs with the truck and hill icon, alerting me that there was a downgrade coming. I was in top/top on a 13 speed and split down to low split in 8th (12 gear). As I passed the sign and entered the downgrade into a narrow winding canyon I was mortified to see "8% Down Grade"!? I immediately braked until my rpm's were about 900-1000 and was able to grab 7th high split (11th gear), then make the split down to 7th low split (10th gear).

I can imagine the terror the rookie driver must have faced in his situation. This is one of the most critical moments in a trucker's life, facing a critical down shift required to control speed.

My method, to use the service brakes to get down to almost lugging the engine, gives me confidence that I have time to get that next gear and if I don't make it the first time I can slightly increase the rpm's as I go for the gear. How do other experienced drivers handle this situation?

 

My rule of thumb is to use at least one less gear going downhill than I would going uphill. This is because the jake brake is going to max out the rpm's in the given gear.

In the case of the Highway 62 experience I had going down to 11th (7th high split on a 13 speed) immediately maxed out the rpm's, so I grabbed 10th (7th low split) to give me some time between using the service brakes to control speed (and allowing the service brakes to cool between applications).

Edited to add: I also braked rather aggressively in that situation on a straightaway, right off the bat as soon as I realized I was facing a downgrade 2% greater than most downgrades. I wanted to do this to make sure I was using fresh, unheated service brakes. The sooner I could control the situation with a lower gear the better.

My brother always preaches a mantra... "Have a plan"... and in this case I made the plan quickly, and executed it perfectly to grab 11th with low rpm's, watched the tachometer climb quickly, reapply service brakes and split to 10th to have a controllable situation. Having a plan before you get there is critical.

 

Part of the reason I posted this was as a sobering note to the dangers of trucking, but also to help relative newbies know that "having a plan" is the first defense against having an accident. When approaching a down grade you are almost always warned with the icon signs with the truck and hill, and below that icon sign is a sign that shows the % downgrade. In the case I noted (62 south of Joshua Tree) they showed an 8% downgrade, with is 2% more than almost any major highway downgrade (usually they are 6%).

The important thing (IMHO) is to control the situation aggressively as early as possible, as soon as you realize you don't have a low enough gear to work with the jake brake, then use the service brakes as fully as possible on a straightaway (or relative straightaway) and get that lower gear.

Never never never (did I say "never"?) brake while in a turn. The momentum of your trailer will go forward while your tractor is going into the turn, an ultimate solution for "How to make my truck to a rollover". If you have to slow down with a curve coming up then BRAKE HARD BEFORE THE CURVE... NOT IN THE CURVE. If the rookie driver had followed this last bit of advise then they may have lived.