Suddenly you note that your trailer has a life of its own. While driving downhill, it starts weaving back and forth by itself and things don't improve when you apply the brakes. You break into a sweat and you're close to panicking.
Your guardian angel is TSATM, which stands for Trailer Stability AssistTM. This is a system that counteracts wobbling and stabilises a trailer that has started weaving back and forth across the road.
The system continuously monitors these wobbling tendencies and compensates by braking 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," explains Per Ola Fuxin, head of vehicle dynamics at Volvo Cars.
Sometimes it can be very difficult to get out of a situation where a trailer has started wobbling, and in the worst case the trailer may even stray onto the wrong side of the road and roll over.
Unfortunately, it is not uncommon for this to lead to severe traffic accidents. These accidents usually occur during vacation periods when the roads are filled with towing caravans, trailers and boat trailers.
"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," concludes Per Ola Fuxin.
The Trailer Stability Assist system is active at speeds above 50 km/h. It is a standard feature when buying a Volvo XC60 with a towing hook.