Holiday travel by car - luggage and roof box
Pack the car for long holiday trips without losing stability, range or legal compliance.
Summer holidays test both planning and driving technique. The weight of the luggage, the aerodynamic drag of a roof box and the distribution of passengers all affect stopping distance, fuel use and stability. This guide shows how to load the car so the trip stays safe, legal and efficient.
Check the total weight first
| Figure | Where to find it |
|---|---|
| Kerb weight | Registration document, field G |
| Gross vehicle weight | Registration document, field F |
| Maximum roof load | Owner’s manual |
| Trailer weight | Registration document, fields O.1/O.2 |
Subtract the kerb weight from the gross vehicle weight - what remains is your payload. Remember that the driver and passengers count too. Read more in Vehicle registration document - overview of all fields .
Packing the rear seats and luggage compartment
- Place heavy objects low and close to the middle to keep the centre of gravity stable.
- Soft items should protect the seat backs; long objects must be secured.
- Luggage nets or straps keep the load in place during hard braking.
- Do not block the rear window - visibility requirements apply all year.
See Securing cargo and passengers for how much force cargo can develop in a collision.
Choosing the right roof box
| Box | Volume | Best suited for |
|---|---|---|
| Small box (300-380 l) | Skis, tent, sleeping bags | Short trips, smaller cars |
| Medium box (400-500 l) | Family holiday of 1-2 weeks | Most common choice |
| Large box (500-650 l) | Camping gear, bulky travel loads | Big families, but more drag |
Use the correct load bars for your car model. Long, low boxes usually give less noise and drag. Remember the maximum roof load - including the weight of the box itself.
Fitting step by step
- Read the instructions for both the roof system and the box.
- Fit the bars as far apart as the box allows.
- Place the box on top, tighten all clamps and test it by rocking it side to side.
- Put the heaviest items low down and centred between the bars.
- Close and lock the roof box, and check that it does not open at 60-80 km/h on an open stretch.
Take a short 5 km test drive before the main holiday trip. Noise or vibration usually means something needs tightening.
How the roof box affects the car
- Aerodynamic drag increases by 20-30%. In an EV, that means noticeably shorter range.
- The car’s centre of gravity moves upward, so drive more smoothly in bends.
- Side wind has more effect. Keep extra distance to trucks and open bridges.
- A road speed limit of 130 km/h does not automatically apply - in Sweden the motorway limit is 130, but the maximum for a car with a roof box is often given as 120 by the vehicle or roof-box system.
Read more in Side wind and wind gusts .
Speed limits and practical limits with a roof box
| Country | Practical limit with a roof box |
|---|---|
| Norway | 110 km/h if the car is approved |
| Sweden | 110 km/h (check the vehicle manual) |
| Denmark | 110-130 km/h on motorways |
| Germany | Recommended 130 km/h |
Manufacturers often set 130 km/h as the maximum. Breaching it can lead to both a speeding fine and loss of insurance cover after a collision.
Fuel use and range
- Petrol or diesel: expect 0.5-1.5 litres more fuel use per 10 km depending on speed.
- EV: up to 30% reduced range in winter conditions.
- Plan charging stops with PlugShare or the vehicle manufacturer’s app.
- Keep average speed below 95 km/h to limit consumption.
Check EV winter range and heat pump before a winter holiday.
Children and passengers in a fully loaded car
- Keep the child seat in the same seat position whenever possible, and recheck ISOFIX after moving it
- Children under 135 cm need proper restraint equipment
- Luggage on the dashboard or parcel shelf can become a projectile in a collision
Read more in Children in the car - restraint equipment .
Common mistakes
| Mistake | Consequence |
|---|---|
| Exceeding the roof load | Damage to the roof and worse road holding |
| Forgetting to retighten the box | Risk of the box coming loose |
| Too much weight at the rear | Light steering axle and weaker control |
| Packing above the line of the rear window | Reduced rearward visibility |
| Forgetting to check tyre pressure | More wear and higher aquaplaning risk |
Smart extra steps
- Make a packing list divided into must have and nice to have
- Use compression bags for clothes and sleeping bags
- Keep important documents such as passports, insurance papers and charging cards within easy reach
- If you bring a dog, secure the crate or use a proper harness
A well-packed car makes for calmer holidays. Check the weight, tyre pressure and roof box one day before departure so you still have time to correct mistakes before the main trip.