To help counteract the weaving of a trailer while, for instance, driving downhill, Volvo designed the Trailer Stability Assist (TSA) to even out the wobbling and stabilize the trailer.
The system works by continuously monitoring the wobbling tendencies of the trailer. When it reads off-the-chart values, it brakes one or more of the car's wheels as necessary. If this is not enough, all four wheels are braked and engine power is cut until control is regained.
"Wobbling is a true nightmare for anyone who regularly tows a trailer of some sort. The problem often occurs, for instance, when a towing caravan that has been incorrectly loaded with too much weight at the very front or very rear," Per Ola Fuxin, Volvo vehicle dynamics head said.
It is obvious why an unstable trailer may be dangerous to motorist. Not only it has the potential to become a road hazard on its own, but it also may draw the vehicle itself into a dangerous situation.
"It is not easy to single-handedly regain control over a trailer that has started wobbling. The basic rule is to always brake. With TSA, the wheels are braked individually, thus counteracting the trailer's weaving tendencies. This is much more effective than the driver braking all the wheels at the same time."
"The other advantage of TSA is that it can activate much earlier to bring a situation under control, perhaps even before the driver notices what is about to happen," Fuxin added.
The Trailer Stability Assist system is active at speeds above 50 km/h. It comes as standard on the Volvo XC60 with a towing hook. It can be used when towing just about everything from a caravan to a boat trailer.