Can you use cruise control when towing?

Once the mark of true luxury in a new car, cruise control has become a staple of modern motoring, with the safety and convenience feature offered in almost every model on the market today in varying levels of sophistication.

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But while cruise-control operation is simple and widely understood, there’s one scenario some drivers are uncertain about – using cruise control when towing.

In simplest terms, cruise control is a system that automatically maintains a vehicle’s speed set by the driver when cruising on freeways or other arterial roads, while more modern adaptive versions regulate a vehicle’s speed up to the set point according to the changing surroundings and traffic.

But what if you hook up a trailer? Does significantly changing the vehicle’s overall GCM (gross combination mass) and performance impact or prevent cruise control’s use?

Put simply: can you still use cruise control if you're towing a trailer?

The short answer is yes. Even relatively primitive cruise-control systems can cope with the variable of changing vehicle weight and the effect it has on driving. In fact, many systems won't even know the extra load is there.

Just as your vehicle can adapt to a steep hill, cruise control simply does as it’s told and will regulate the throttle and brake to maintain the selected speed.

Actually, cruise control can offer the same advantages when towing as it does when the vehicle is unloaded.

Firstly, smooth and minimal adjustments of the accelerator help to minimise fuel use, and this is only amplified when towing. Motorists who tow for long distances may notice a difference in fuel consumption after switching to a vehicle with cruise control.

Then there’s the safety element – setting a maximum vehicle cruising speed when covering lots of kilometres avoids a drowsy or distracted driver creeping over the speed limit. We probably don’t need to highlight the implications of incidents on the road when vehicle size and weight increase.

The cleverest cruise-control systems will go even further.

The most advanced vehicle systems will sense that a trailer has been connected to the vehicle and adjust some of its functions accordingly. These include ignoring or adapting blind-spot monitoring, which can be confused into thinking the trailer is an approaching vehicle.

Other systems will also compensate for the caravan or other towed objects and allow extra space for automatic lane changes. More advanced radar systems will switch off rear alerts to prevent annoying beeps when reversing a trailer.

There’s really only one situation in which cruise control’s operation can be affected while towing and that’s in the most extreme loading cases.

If the vehicle’s GCM has increased to a point that exceeds its performance, the van or ute might simply be unable to achieve the speed requested by the driver. In this case, the vehicle will do the best it can given its power and torque limitations.