Recently, due to fires in the Outeniqua mountains, drivers had to take a detour from Oudtshoorn to George via the Robinson pass towards Mossel Bay.
The Robinson pass is much more of a challenge for truck drivers as there are no “extra lanes” and the corners tend to be much sharper than on the Outeniqua pass.
It was quickly evident that motorists became frustrated with the delays as they shared the mountain pass with much slower carriers of road freight.
We believe it may be important to share some content on safety advice for truck drivers – and not only that but also to create a greater understanding among motorists about the challenges facing our truck drivers when driving in the mountains and mountain passes.
We approached some of the leading driver training specialists in South Africa with the following Q&A:
In truck crashes, the causes can probably be divided into a shared cause dynamic: Human and Mechanical. But there’s a caveat…
Due to the nature, design and physical size of trucks, human usage patterns can lead to mechanical failure; which is not mutually exclusive.
In a light motor vehicle, you practically have to race on a track and really abuse the brakes – for instance – before the braking capacity would deteriorate to the point where the vehicle becomes mechanically unsafe.
With trucks, the sheer size and momentum results in much greater friction forces, greater temperatures because of it and much sooner failure of components.
If you drive a car down a long mountain pass, you could free-wheel, brake and apply engine braking interchangeably and still travel down the pass safely – the car is relatively small and light and carries very little weight, compared to its own weight.
Take a so-called “1-ton LDV” as an example. If it weighs about 1,500Kg empty and is loaded to full capacity, the total mass is never more than about 2,500 Kg. This means that the vehicle is only carrying about an additional 55% of its own weight. Let’s talk about a truck of about 8,500Kg with a trailer of about 6,000Kg. That’s 14,500Kg in total. But… It could carry 30 tons or 30,000 Kg. That’s more than twice its own weight, being transported.
Simply put – cars are not trucks. Trucks carry greater loads, have more momentum, are articulated, etc.
Over-use of any of the systems likes brakes, engine, retarders, etc, can result in extremely abnormal wear or friction/loading dynamics which can lead to failures – like failed brakes – or systemic failures like skipping a particular gear and not being able to engage it again.
Because maintaining control of a truck – especially on treacherous roads – involves a combination of systems – brakes, engine retardation through gears, gear choice, retarder and brake system pressure – over-use or irregular use can cause one of the multiple systems to fail or conspire, which can result in collisions or fatalities.
To get back to the question – the most prevalent factor that leads to truck crashes would be a lack of understanding of the fine balance between the various systems. This may lead to a failure in avoiding overheating brakes and under-utilising their exhaust brakes assistance which is available to them to avoid overheating the brake system.
Human factors would also include lack of concentration as the speed requirement differ so much on up and down hills. On an up-hill due to the slow speed, drivers lose concentration and frequently do not select correct gears for climbing.
The environment very seldom features as a cause of specifically truck collisions. Mechanical failure very often results from poor use cycles, which is the result of driver error, or human factor.
A word of appreciation to the following for their assistance