Roof box: key precautions before travelling on holiday

Getting a car ready for the holidays can be tricky, particularly when the boot simply doesn’t have enough room. That’s a familiar problem, especially for larger families or those travelling with young children.

For many drivers, the answer is a roof box. It’s a convenient way to boost a car’s load capacity, above all at the times of year when that extra space is most needed. Even so, as helpful as it is, carrying luggage on the roof calls for extra care and a few specific precautions.

Choosing to fit a roof box without thinking about limits (weight and capacity), the mounting points, and proper weight distribution can put safety at risk, increase fuel consumption, and even cause damage to the vehicle. With that in mind, we’ve gathered the key points every driver should consider before putting a roof box on the roof.

Check the roof load limit

Before fitting any accessory to your car’s roof, you need to know the permitted roof load, which is set out in the vehicle’s handbook. This figure includes the weight of the roof bars and the roof box itself, as well as the luggage you place inside it.

Exceeding that limit can reduce the car’s stability, make it harder to drive, and may even damage the structure. It’s also essential to confirm the roof bars are compatible with your vehicle and that they are securely fitted before you set off.

Distribute the weight evenly

How you pack the roof box matters. Heavier items should sit in the middle, with lighter items towards the ends. Poor distribution shifts the car’s centre of gravity and increases the risk of a rollover, particularly on bends or in strong crosswinds.

It’s also worth remembering that any extra weight on the roof-even if it seems small-can change the way the car behaves compared with what you’re used to. Finally, make sure your luggage is properly restrained, as loose items can be thrown about if you brake sharply.

When driving, keep in mind that a roof box creates more wind resistance, which affects both fuel consumption and stability. For that reason, avoid sudden overtakes, fast cornering and high speeds, especially on motorways.

On longer journeys, it’s sensible to stop more often, even if only to check that the roof bars and the roof box are still firmly secured, helping to prevent shifting or an unexpected opening.

Pay attention to the vehicle height

Another important consideration is that roof boxes significantly increase the overall height of the car.

So, make a note of your vehicle’s height with the roof box fitted and stick to maximum height restrictions in underground car parks, as well as when approaching bridges or tunnels, to avoid accidents and costly damage.

Check your insurance policy

Some insurers require you to declare external luggage transport or to ensure the load is properly secured. Review the details of your policy before travelling to avoid complications if an accident occurs.