Johan is a particularly impressive man, with great knowledge. I value his expertise anywhere. Still, extremely slippery ice and snow is relatively less important in the southern hemisphere, although again, south america has much higher mountains than the rest of us enjoy.
One other component that Johan can expand on, is that i see some European trucks are running very high tyre pressures, I've read of pressures of 10 bar!, at least that is what I have read, as I have not had the pleasure of visiting there. Maybe Johan will invite me one day.....
another thing, drive tyre pressures are vital for semi and b double stability. I believe that drive tyre traction is paramount for minimizing the classic semi problem of jack knifes. Records show that an empty or lightly loaded semi is 2.5 times more likely to jack knife, which is in Johan's picture. With a lightly loaded semi or B double, the drive tyres will have 200 to 300% excessive tyre pressures. My customers, mostly B doubles, regularly run at 30 psi, 2 bar, in the drive tyres on the highway, with great experiences, with maybe 6 tonne on 8 tyres. I regularly run 25 psi on my single axle prime mover on highways. I have Michelin tyre charts showing the optimum pressures at these loads.
To further provide understanding, a toyota landcruiser typically weighs 2.8 to 3 tonnes on the road. Their recommended pressure on much smaller tyres is only 35 psi, or around 2.4 bar. That is 750 kg on small four wheel drive tyres, compared to 750 kilos on much bigger and stronger tyres....
So, yes, ice is terrible for traction. yes, Johan is quite right, many truck drivers do not load the drive tyres sufficiently. I see every day empty tip trucks (dump?) pulling a proper trailer with an excavator or similar. Our rules state that the truck (tractor yankee language) should weigh more than the trailer, but no one enforces it cause everyone breaks the rule. Improper loading along with poorly balanced brakes, combined with exceedingly high tyre pressures is a guarantee for problems.
In less slippery terrain, like loose gravel, and dirt roads, or sand, my customers would laugh at the idea that B doubles are dangerous. They push the button on the dash, drop the drive tyre pressures down to 30 (two bar) and go into and out of places a standard semi can't go, with conventional pressures. I go lower, as do a few of my customers. I regularly go down to 16 psi (1.1 bar), and it is amazing where we go. With a full load, you don't turn very sharp, but, the traction is awesome.
Hope that helps.
Chet
road-transport-technology.org
Granlund & Thomson at International HVTT14 Symposia: Traffic Safety Risks with EU Tractor-Semitrailer Rigs on Slippery Roads 2 1. Background
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lovdata.no
§ 1-2. Definisjoner. Definisjonene i vegtrafikkloven og i forskrift 25. januar 1990 nr. 91 om krav til kjøretøy, forskrift 4. oktober 1994 nr. 918 om tekniske krav ...
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