Why Does Fuel Economy Drop on Summer Road Trips?

Many drivers assume highway driving always gives the best fuel economy. While that is often true, several factors can quickly reduce your kilometres per litre on a summer road trip.

If you’re heading to Grand Beach, Riding Mountain, Whiteshell, Clear Lake, or beyond, here are the biggest reasons your vehicle may use more fuel than you expected.

1. Does Driving Faster Use More Fuel?

Yes.

Once you reach highway speeds, wind resistance becomes one of the biggest factors affecting fuel economy.

Driving at 110 km/h instead of 100 km/h may not seem like much, but your engine has to work harder to push through the air.

If you’re not in a hurry, maintaining a steady speed can help reduce fuel consumption.

Adaptive cruise control or regular cruise control can also help by avoiding unnecessary acceleration.

2. How Much Extra Weight Are You Carrying?

Every cooler, suitcase, camping chair, and bag adds weight.

While a few items may not make much difference, a heavily loaded vehicle requires more energy to accelerate and maintain speed.

This is especially important for families taking longer vacations or camping trips where cargo space fills up quickly.

A good rule is to pack only what you actually plan to use. Removing unnecessary items before departure can help improve fuel economy and reduce strain on the vehicle.

3. Do Roof Boxes Affect Fuel Economy?

Yes. More than many people realize.

A roof box creates extra wind resistance.

Even when it’s not full, it changes the way air flows over your vehicle.

This can increase fuel consumption, especially on highways.

If you only use a roof box a few weekends each year, consider removing it when you’re not travelling.

4. Are Bike Racks Better on the Roof or Hitch?

A hitch mounted bike rack is usually more efficient.

Roof mounted bikes create more wind resistance and can reduce fuel economy.

They also increase vehicle height, making it easier to forget about low parkades or drive-throughs.

If your vehicle has a hitch, a rear mounted bike rack is often the better choice.

Keep in mind, whether mounted on the roof, hitch, or rear of the vehicle, bike racks create additional aerodynamic drag. The effect becomes even greater when carrying multiple bicycles.

5. Does Towing Change Fuel Economy?

Absolutely.

Pulling a camper, boat, or utility trailer increases weight and wind resistance.

Fuel economy can drop significantly when towing, especially at highway speeds.

If you’re towing:

• Accelerate smoothly.
• Leave more space when braking.
• Drive at a steady speed.
• Avoid carrying unnecessary cargo in both the trailer and the vehicle.

6. Have You Checked Your Tire Pressure Recently?

Tire pressure is one of the simplest factors to overlook and one of the easiest to correct.

Underinflated tires create greater rolling resistance, which means the engine must use more fuel to keep the vehicle moving.

Tire pressure can also fluctuate with changing temperatures. A vehicle that was properly inflated earlier in the year may no longer be at the recommended pressure heading into summer travel.

Before every road trip:

• Check tire pressure when the tires are cold.
• Inflate them to the manufacturer’s recommended pressure.
• If your vehicle is heavily loaded, check whether a higher pressure is recommended in your owner’s manual.

Proper tire pressure also improves handling and helps your tires wear more evenly.

7. Can Cruise Control Save Fuel?

Usually, yes.

On long, flat highways, cruise control helps maintain a consistent speed and reduces unnecessary acceleration.

However, on steep or rolling hills, it may keep the throttle open longer than a driver would naturally.

In those situations, slight manual speed adjustments can sometimes improve fuel economy.

8. Does Air Conditioning Use More Fuel?

A little.

Air conditioning does increase engine load, but on most highway trips the effect is relatively small.

Opening the windows at higher speeds can create extra wind resistance, which may reduce fuel economy even more.

On the highway, using the air conditioner with the windows closed is often the more efficient choice.

 

Simple Ways to Use Less Fuel This Summer

Before your next road trip:

• Remove roof boxes and bike racks if you don’t need them.
• Check your tire pressure.
• Pack only what you’ll use.
• Drive at a steady speed.
• Avoid sudden acceleration.
• Plan your route to reduce unnecessary detours.

Small changes can add up over a long drive.