Slippery roads and downhill gradients during winter can often present a tough challenge for skilled drivers, as there is always the risk of the truck and trailer combination starting to jack-knife.
Volvo Trucks has developed a system known as Stretch Brake that automatically brakes the trailer and straightens up the combination on slippery downhill stretches.
Even if the driver manages to control the situation, it can be extremely unpleasant, if a combination suddenly veers off its intended course on a downhill gradient,” says Volvo Trucks brake specialist Mats Sabelström.
About 15% of the 30,000 serious road accidents in Europe every year involve trucks.
“Stretch Brake is yet another important part of our long-term drive to increase traffic safety and minimise the number of accidents involving trucks,” says Volvo Trucks traffic and product safety director Carl Johan Almqvist,
Stretch Brake is a complement to the combination’s electronic stability program (ESP). While ESP is at its most effective at higher speeds, Stretch Brake is only operational at speeds below 40 km/h. Both systems contribute to better stability and easier steering.
“One might call Stretch Brake a kind of low-speed ESP. As the combination approaches a downhill slope, the driver manually activates the system. When the driver then releases the accelerator, the brakes on the trailer are automatically applied in a pulsated mode all the way down the hill until the gradient levels out and speed can be increased once again,” says Mats Sabelström.
Stretch Brake was introduced in 2012 on Volvo FH trucks pulling conventional drawbar trailers and in 2013 on Volvo FM trucks pulling drawbar trailers. In 2014 it will also become available for Volvo FH and FM semi-trailer combinations.
According to the Volvo Trucks accident research team, which specialises in studying traffic safety, about 60 or so of the truck accidents that occurred in Sweden alone last year could have been avoided with Stretch Brake2.
