Diesel is one of the biggest operating expenses for truck drivers, and it doesn't take much for fuel costs to cut into your margins. Whether you're an owner-operator or managing a fleet, fuel is one of the few major expenses you can directly influence.
Your driving habits, maintenance schedule, route planning, and fuel purchasing tools all affect how much diesel you burn and what you pay at the pump. This guide breaks down practical ways to reduce diesel costs both immediately and over the long term.
Key takeaways
- Slowing down pays off. Reducing your highway speed from 75 mph to 65 mph can improve fuel economy by up to 22%, which adds up fast over thousands of miles.
- Idling burns more fuel than most drivers realize. A typical diesel engine burns roughly 0.8 gallons of fuel per hour at idle, making unnecessary idling one of the easiest costs to reduce.
- Tire pressure directly affects fuel economy. Underinflated tires increase rolling resistance, forcing your engine to work harder and burn more fuel.
- Smarter route planning reduces wasted fuel. Out-of-route miles and congestion-related stop-and-go driving both increase diesel costs.
- Fuel cards can lower your cost per gallon. The OTR Fuel Card offers average savings of $0.50 per gallon and up to $2.25 per gallon at select in-network locations.
How can truck drivers save on diesel fuel?
Truck drivers can save on diesel fuel by improving driving habits, maintaining their trucks, planning smarter routes, and using fuel purchasing tools like fuel cards. Small changes across these areas add up quickly and can significantly lower fuel costs over time.
Quick ways to save on diesel fuel
- Drive between 55 and 65 mph to improve fuel economy
- Avoid idling longer than 3 to 5 minutes when possible
- Keep tires inflated to the recommended pressure
- Use cruise control on flat highways
- Plan routes around traffic and congestion
- Use a fuel card for per-gallon discounts
Improve driving habits to save fuel
Small changes to how you drive can have a major impact on fuel economy. The way you manage your speed, throttle, and idle time all affect how much diesel your truck burns on every run.
Reduce highway speeds
Driving at highway speeds is one of the biggest drivers of fuel consumption. The faster you go, the more aerodynamic drag your truck fights. According to research from ATRI, driving at 65 mph can yield up to a 22% improvement in fuel economy compared to 75 mph. If you're fueling multiple times a week, that difference is real money.
It helps to think in dollar terms: if fuel is $3.50 per gallon and your truck gets 6 mpg at 65 mph versus roughly 4.5 mpg at 75 mph, the savings per mile are significant. Over a month, consistently driving slower can save hundreds of dollars without changing anything else about your operation.
Minimize idling time
A diesel engine running at idle burns approximately 0.8 gallons of fuel per hour. Over time, that fuel usage becomes a significant expense. If you idle for two hours a day across a five-day week, that's 8 gallons you're burning without moving an inch.
Some situations make idling unavoidable, including:
- Extreme cold weather that requires maintaining cab temperature
- Regulations that require the engine to stay running
- Mandatory rest periods where climate control is needed
Outside of those situations, reducing idle time during breaks and extended warmups is one of the easiest fuel-saving adjustments you can make.
Accelerate and brake smoothly
Stop-and-go driving wastes fuel. Every time you brake hard, you lose the momentum your engine worked to build. Every time you accelerate aggressively, your truck burns more diesel than necessary. Driving smoothly and maintaining a consistent speed reduces both fuel usage and brake wear.
This matters most in congested areas. If you can see traffic slowing ahead, easing off the throttle early instead of braking hard at the last second keeps your truck moving efficiently and helps reduce overall fuel costs.
Use cruise control strategically
Cruise control can improve fuel economy when used in the right conditions. On flat, open highways, maintaining a consistent speed with cruise control typically delivers better efficiency than constant manual throttle adjustments. It eliminates the small speed fluctuations that add up over long stretches of highway.
That said, cruise control works against you on hilly terrain or in traffic. On steep grades, cruise control may overwork the engine during climbs and accelerate too aggressively on descents. Reserve it for long, flat runs where it delivers the most benefit.
Keep your truck properly maintained
A well-maintained truck runs more efficiently. When components are worn, dirty, or underperforming, your engine has to work harder and burn more fuel. Staying on top of routine maintenance is important for your truck’s longevity and directly affects fuel costs.
Maintain proper tire pressure
Tires are one of the most fuel-sensitive components on your rig. When tires are underinflated, more of the tire surface contacts the road, increasing rolling resistance and forcing your engine to work harder. EPA SmartWay notes that truck tires inflated 10 psi below the recommended pressure can reduce fuel economy by 0.5% to 1%.
Check tire pressure at every pre-trip inspection. Using a digital gauge takes less than five minutes and can save you money on every load. Dual tires and trailer tires are especially easy to overlook, but they matter just as much as steer tires.
Replace air filters and maintain engine health
A clogged air filter restricts airflow to the engine, reducing combustion efficiency and increasing diesel usage. Replacing a dirty air filter is one of the lowest-cost maintenance items with the biggest potential return. Most manufacturers recommend checking air filters every 15,000 to 30,000 miles, though actual replacement intervals depend on your driving conditions.
Dusty or unpaved routes wear out filters faster. If you're regularly driving in those environments, inspect your filter more often. A clean air supply helps your engine run efficiently without compensating for restricted airflow.
Use the right oil and perform regular service
Engine oil reduces friction between moving parts. When oil levels are low or the wrong viscosity is used, internal friction increases and the engine has to work harder. Follow your manufacturer's recommended oil change intervals, use the correct oil type, and avoid delaying service to save a few dollars upfront.
Routine maintenance, including fuel filter replacements, injector inspections, turbo maintenance, and regular fuel system cleaning, helps keep your engine operating efficiently. Deferred maintenance can gradually reduce fuel economy and lead to more expensive repairs over time.
Check for fuel leaks and inefficiencies
Small fuel leaks may seem minor, but they add up quickly. A slow drip from a fuel line or injector seal can waste several gallons over the course of a week. Beyond the direct fuel loss, leaks can also create safety hazards and lead to larger mechanical problems if left unresolved.
During your pre-trip inspection, look for fuel odors, staining around fuel lines, or visible drips near the tank or injectors. Catching a small leak early is far less expensive than dealing with a larger repair later.
Plan smarter routes to avoid wasted fuel
Where you drive and how you get there have a direct impact on fuel usage. Route planning is often treated as a time management tool, but it also plays a major role in fuel efficiency.
Avoid traffic and congestion
Stop-and-go traffic is one of the worst conditions for fuel economy in a diesel truck. Every deceleration and re-acceleration cycle burns fuel without adding meaningful mileage. If your route takes you through a high-congestion area during peak hours, adjusting your departure time or taking an alternate route can help reduce fuel costs.
This is especially worth considering in metro delivery areas or around port facilities where traffic patterns are predictable. It can also become more important during peak produce shipping seasons, when freight volumes increase and congestion along major shipping corridors becomes more common. In some cases, a 20-minute detour around a congested stretch may use less fuel than sitting in stop-and-go traffic for the same amount of time.
Reduce out-of-route miles
Deadhead miles are already expensive, but unnecessary out-of-route miles during loaded runs add even more cost. Every extra mile that isn't contributing to your rate is a direct hit to your fuel budget. Reviewing your route before departure and identifying unnecessary detours is a simple way to protect margins.
This also applies to fuel stops. Driving several miles off-route to reach a cheaper fuel stop can easily eliminate the savings you were trying to gain. The best fuel stop is one that's along your route and offers real per-gallon savings, not just a lower posted price.
Use fuel price and route planning tools
Fuel prices can vary significantly between locations, making price comparison an important part of route planning. Fuel Finder in the OTR Mobile App helps drivers compare exclusive discounts along their route so they can identify the best fuel stops before leaving the highway.
Pairing smart route planning with fleet and fuel management tools gives you a clearer picture of overall fuel spend, not just the cost of a single fill-up.
Use fuel purchasing strategies to lower cost per gallon
Driving habits and maintenance help reduce how much fuel your truck burns. Fuel purchasing strategies help lower how much you pay per gallon. When used together, they give carriers more control over overall fuel costs.
Use fuel cards to access discounts
Fuel cards give drivers access to pre-negotiated pricing at in-network locations, which is often lower than the retail price posted at the pump. Instead of chasing the cheapest advertised diesel price each day, fuel cards provide more predictable savings across thousands of locations nationwide.
The OTR Fuel Card is built around that same model. Cardholders receive:
- Accepted at 8,000+ locations nationwide, with 3,000+ in-network locations
- $0 transaction fees at every in-network stop
- Average savings of $0.50 per gallon, with exclusive discounts up to $2.25 per gallon at select locations
Those savings come from direct relationships with the country's top fuel chains, not from fluctuating retail price comparisons.
The OTR Fuel Card is available as a prepaid or credit-based option, so you can choose what works best for your operation. Neither requires a credit check to apply. With the prepaid fuel card, you load funds before first use and spend your own money on fuel purchases.
Drivers who prefer the credit-based option can cover fuel expenses upfront and settle the balance on a weekly billing cycle through a fuel card line of credit.
Avoid high-priced truck stops
Not all truck stop pricing is equal, even within the same chain. Locations near state lines, toll roads, or high-traffic corridors tend to charge a premium on retail diesel. Knowing how to find the cheapest diesel fuel can help drivers avoid overpriced stops and reduce overall fuel costs. Rural locations and stops that are slightly off the beaten path often post lower retail prices.
This is another area where having a fuel card with a network-based discount matters. The discount is applied on top of local pricing, so starting from a lower retail base at the right location compounds your per-gallon savings.
Time fuel purchases strategically
Diesel prices follow regional and seasonal patterns. Prices in California and the Northeast consistently run higher than in the Midwest and South. If your route takes you through lower-cost regions, topping off there rather than waiting until you're in a high-cost area is an easy way to reduce your average cost per gallon.
Fuel prices follow crude oil markets, shifting with refinery output, seasonal demand, supply chain conditions, and regional fuel requirements like ultra-low sulfur diesel. Understanding pricing trends along your regular routes can help you decide when and where to fuel. Pairing those decisions with a strong fuel management strategy can help control costs across every run.
Extra ways to reduce diesel costs
Once you've improved your driving habits, maintenance routine, and fuel purchasing strategy, these additional adjustments can help reduce fuel costs even further
Reduce truck weight when possible
Heavier trucks burn more fuel. Extra weight forces the engine to work harder, so removing unnecessary cargo, equipment, or accessories can help improve efficiency.
This matters most on loaded runs where you're close to weight limits, but it also applies to tools, spare parts, and anything else carried regularly in the cab or sleeper. Periodically reviewing what you're hauling can help eliminate unnecessary weight and improve fuel economy over time
Improve aerodynamics
Aerodynamic drag increases significantly at highway speeds. Most modern trucks include features like cab fairings, side skirts, and aerodynamic mirrors, but older equipment may not have all of these efficiency upgrades. Aftermarket side skirts and trailer nose fairings can help reduce drag and improve highway fuel efficiency.
Even small adjustments, like keeping cab-mounted accessories streamlined and ensuring trailer doors are properly sealed, can help reduce aerodynamic resistance. A full aerodynamic package may improve fuel economy by 5 to 10% on highway routes, which can add up quickly at current diesel prices.
Use fuel additives when applicable
Diesel fuel additives can help improve combustion efficiency and protect fuel system components, especially during colder months. Winter-blend diesel fuel already includes additives to help prevent gelling, but supplemental additives may improve cold-weather starting and overall performance during extreme temperature drops.
Not all additives deliver meaningful benefits under normal driving conditions, so it's worth consulting a diesel mechanic before adding anything to your fuel system.
Monitor fuel efficiency metrics
You can't improve what you don't measure. Tracking your semi-truck fuel economy consistently, whether through your truck's onboard computer or a third-party ELD, can help identify fuel efficiency issues before they become larger problems.
A sudden drop in mpg that isn't explained by terrain or load weight is often a sign of a maintenanc issue. Regular monitoring helps catch these problems early before repair costs and fuel waste compound over time. Establish a baseline for your typical mpg on regular routes and pay attention to significant changes.
Frequently asked questions
How can I reduce diesel fuel consumption immediately?
Slow down. Reducing your highway speed from 75 mph to 65 mph is the single fastest way to cut fuel consumption without spending any money. Combine that with avoiding unnecessary idling and using smooth acceleration, and you'll see results on your next run.
What is the cheapest way to buy diesel fuel?
A fuel card with network-based discounts gives you the most consistent access to below-retail pricing. The OTR Fuel Card provides average savings of $0.50 per gallon and exclusive discounts up to $2.25 per gallon at 3,000+ in-network locations, with no transaction fees at those stops.
Do fuel cards really save money?
Yes, when the card is tied to a network with pre-negotiated pricing. Cards that rely on retail price comparison or rebate programs offer less predictable savings. The OTR Fuel Card gives you exclusive discounts at the pump, so the savings show up immediately when you fill up at in-network locations.
What is the most fuel-efficient speed for a semi-truck?
Most diesel semi-trucks achieve their best fuel economy between 55 and 65 mph. Fuel consumption increases significantly above 65 mph due to aerodynamic drag. At 75 mph, a truck can burn 25% more fuel than it would at 65 mph on the same route.
How much fuel does idling use?
A typical diesel engine burns approximately 0.8 gallons of fuel per hour at idle. Over the course of a week, even a few hours of daily idling adds up to real money. Limiting idle time to what's operationally necessary is one of the easiest ways to reduce fuel costs without any upfront investment.
Small changes add up to big fuel savings
Better driving habits, consistent maintenance, smarter routes, and the right fuel card all work together, and the biggest gains come from using them in combination.
The OTR Fuel Card gives you access to exclusive per-gallon savings at 3,000+ in-network locations, with $0 transaction fees and no credit check required. Factoring clients can also access a fuel card line of credit, covering fuel expenses and settling the balance on a weekly billing cycle. Pair your fuel card with True Non-Recourse Factoring, and you get same-day funding on approved and processed invoices alongside consistent fuel savings, managed in one place through the OTR Mobile App.
%20%20(1).png)
