Fuel Efficiency Myths in Trucking: What Really Works and What’s Just Talk
Fuel costs remain one of the most pressing concerns for carriers, owner-operators, and fleet managers. With diesel prices fluctuating and fuel often accounting for 30–40% of operating expenses, any potential savings at the pump quickly grab attention.
Unfortunately, the trucking industry is full of fuel-saving “tips” that range from outdated advice to outright myths. Acting on bad information can waste time, cost money, and distract from the real strategies that deliver results.
This guide separates fact from fiction, explaining which methods truly improve fuel efficiency — and which ones simply don’t live up to the hype.
1. Myth: Higher Speed = More Loads and More Profit
The Claim: Driving faster means you complete trips sooner, fit in more loads, and make more money.
The Truth:
While shaving an hour or two off transit time might seem like a win, increased fuel burn often cancels out the financial benefit. Fuel efficiency drops rapidly above 65 mph — every additional 1 mph above that threshold can reduce MPG by 0.1–0.2.
What Works Instead:
- Find your truck’s “sweet spot” for MPG, usually 60–65 mph.
- Plan to avoid unnecessary rushes.
- Optimize load scheduling to balance delivery windows with fuel savings.
2. Myth: Idling Isn’t a Big Deal
The Claim: It’s fine to idle for long periods — it barely affects fuel costs.
The Truth:
Idling consumes roughly 0.8 gallons per hour for most diesel engines. For drivers idling overnight for climate control, that can mean 8–10 gallons wasted in a single rest period — costing hundreds of dollars per month.
What Works Instead:
- Use auxiliary power units (APUs) or bunk heaters/coolers.
- Park strategically for natural ventilation or warmth.
- Limit idling to necessary warm-up and cool-down periods.
3. Myth: Bigger Engines Are Always More Fuel Efficient
The Claim: More horsepower means less strain and better MPG.
The Truth:
A larger engine can handle heavy loads more easily, but it doesn’t necessarily improve MPG — especially for lighter loads or flat routes. In many cases, larger engines burn more fuel in normal operation.
What Works Instead:
- Match engine size to your freight profile and operating lanes.
- Maintain the engine for optimal performance, regardless of size.
4. Myth: Rolling Down Windows is Better Than Using A/C
The Claim: Turning off the air conditioning and rolling down the windows saves fuel.
The Truth:
At low speeds, this can help slightly. At highway speeds, open windows create drag — often increasing fuel consumption more than running the A/C.
What Works Instead:
- Use A/C wisely — avoid “max cool” unless needed.
- Ventilate naturally at low speeds and in cooler weather.
- Maintain your A/C system for efficiency.
5. Myth: Cruise Control Always Saves Fuel
The Claim: Using cruise control is always the most fuel-efficient option.
The Truth:
On flat terrain, cruise control is great for maintaining steady speeds and saving fuel. On hilly or mountainous routes, however, it can cause unnecessary acceleration uphill and over-throttling downhill.
What Works Instead:
- Use cruise control on steady, flat routes.
- Switch to manual throttle control in hilly terrain.
6. Myth: Tire Pressure Only Affects Safety
The Claim: Proper tire pressure is mostly about preventing blowouts, not fuel economy.
The Truth:
Underinflated tires increase rolling resistance, forcing the engine to burn more fuel. Just a 10 psi drop can reduce fuel efficiency by 1–2%.
What Works Instead:
- Check tire pressure daily or use TPMS (Tire Pressure Monitoring Systems).
- Maintain alignment and rotate tires regularly.
7. Myth: Premium Diesel Always Gives Better MPG
The Claim: Higher-grade diesel burns cleaner and delivers better mileage.
The Truth:
Premium diesel may improve lubricity and reduce deposits, but MPG gains are minimal and rarely offset the extra cost.
What Works Instead:
- Use standard diesel from reputable stations.
- Add fuel treatments only in extreme conditions (very cold weather, poor fuel quality).
8. Myth: You Need to Keep the Tank Full to Save Fuel
The Claim: A full tank improves efficiency and prevents condensation.
The Truth:
While it helps prevent condensation, it doesn’t significantly affect MPG — and extra weight from a full tank can slightly reduce efficiency.
What Works Instead:
- Fuel based on trip length and price locations.
- Reduce unnecessary weight wherever possible.
9. Myth: Aerodynamic Devices Are Just for Looks
The Claim: Side skirts, trailer tails, and other aerodynamic tools don’t make a difference.
The Truth:
Proven aerodynamic devices can improve MPG by 2–8%. At 100,000 miles/year, even a 3% gain can save over $2,000 in fuel.
What Works Instead:
- Invest in proven aerodynamic upgrades.
- Combine them with fuel-efficient driving habits.
10. Myth: Shorter Routes Always Save Fuel
The Claim: The shortest route is always the cheapest.
The Truth:
Shorter routes may involve more stops, traffic, or steep grades — all fuel drains. A slightly longer route with steady speeds often burns less fuel.
What Works Instead:
- Use routing software optimized for MPG, not just miles.
- Factor in terrain, traffic, and average speeds when planning routes.
What Works for Fuel Efficiency
The most effective ways to save fuel in trucking include:
- Slowing down to your truck’s optimal speed.
- Reducing idle time with APUs or efficient rest strategies.
- Maintaining proper tire pressure and alignment.
- Keeping up with engine and drivetrain maintenance.
- Using aerodynamic enhancements to reduce drag.
- Optimizing routes for steady speeds and fewer stops.
- Driving smoothly with minimal hard acceleration/braking.
These strategies may not be flashy, but they consistently deliver measurable savings for fleets and Owner Operators alike.
