Today's Trucking
products Brakes

BRAKING ON BLACK ICE

Posted: August 1, 2014 by Passenger Service: State troopers ride-along with truckers in crash study

From the January/February 2002 issue.

Operating in the winter weather conditions that blanket much of this Great White North is routine for the average Canadian truck driver. But that doesn’t mean, as Dennis Pettit says, drivers should get too comfortable. Here, in
question-and-answer form, the safety manager at Calgary-based Canadian Freightways offers the tips he gives his own drivers for handling black ice.

Today’s Trucking: Normally, you can’t see black ice on the road, except for maybe
a shiny or wet-looking sheen on the asphalt. What do you tell your drivers about
how to watch out for this stuff?

DENNIS PETTIT: Black ice forms first and stays frozen longer on bridges and
overpasses, or in heavily shadowed areas like the base of a mountain. But really,
you can find black ice just about anywhere it’s below freezing. Because black ice
forms when the temperature drops quickly, it’s important to know how cold it is
outside. We equip all our trucks with thermometers. Say you’re going between
Calgary and Vancouver. You might be going through four different weather zones.

You want the driver to be watching the temperature and looking out for things like
melting snow on the side of the road.

TT: How do you know you’ve hit black ice?

DP: Let’s put it like this: when the truck becomes really quiet, you’re in trouble.

Your road noise disappears because your tires are no longer in contact with the
asphalt. They’re running on a thin layer of ice instead.

TT: So how do you slow down? Just ease off the throttle?

DP: First you want to make sure you have the engine brake shut off. Guys like to
run with it on and then forget about it. When they hit moisture or ice, without
thinking, they come off the throttle and the engine brake kicks in. On an engine with electronic controls, all that braking horsepower will lock up wheels. Without any traction, the truck will go out of control and start to slide sideways.

TT: If a driver does have his engine brake engaged and he starts to slide, what can he do to save himself?

DP: Like I said, he shouldn’t have it on to begin with. But if he does, you want him to get it off as quickly as he can and stay the heck away from the brakes because
that’s going to make it worse. And then go to your clutch.

TT: What you say about engine brakes could apply to cruise control, too?

DP: Our policy here is if you’re driving in wet or icy road conditions, shut off the
cruise. The opportunity for loss of control if you have the cruise on increases in
slippery conditions. What happens, especially if you’re in a bit of a pull already, is the wheels don’t have traction and they spin. Gravity tries to slow you down, and your wheels are pushing to make you move. The minute you hit black ice in
particular, you’re going to lose traction and spin out.

TT: So you’re in a Catch 22 if you touch your brakes to disengage the cruise?

DP: Sure, it’ll kick out. But if you’re on ice, the last thing you do is touch your
brakes.

TT: What if you’re heading down a hill that looks dangerous?

DP: The key is to go easy on the brakes. You want to use a gentle touch, pumping them gently at a fairly rapid sequence, without a lot of pressure. You just want to
use enough application to hold you back slightly. If you’re going down a hill, you
also want to be in a lower gear. A good rule of thumb is you go down the hill in the
same gear you climb it.

Also, one thing I’ve always said is that tire chains are needed to go down hills as
well as climb them. If there’s any risk of losing control, you want to pull over and put your chains on.

TT: Winter driving is tough mentally. It’s stressful. What do you want your drivers
thinking about when they’re out in such conditions?

DP: There’s nothing stopping you from putting yourself in different scenarios while
you’re driving. Look ahead up the road and figure out your escape move if something happens suddenly in front of you. Ask yourself what you would do if you lost your brakes right there, for example.

In general, you always want to have control of the vehicle, expecting the
unexpected.

Share

  • This field is for validation purposes and should be left unchanged.
Related Articles
TodaysTrucking
TruckNews