AUTONEWS

When diesel prices rise, every freight mile matters

The price on a fuel pump is easy to see. The miles embedded in everything you buy are harder to track.

Before a bag of rice reaches a grocery shelf or a replacement part arrives at a factory, it travels through a physical network of highways, rail lines and connections. When diesel gets expensive, those journeys become more expensive, too. 

On Oct. 20, the national average price of diesel stood at approximately $6.32 a gallon, compared with $3.62 a year earlier, according to AAA.

Understanding how far goods must travel helps experts assess freight costs. Researchers at Arizona State University have developed a more realistic way to estimate those miles, calculating distances along the highways and railways goods use instead of straight lines between locations.

Their study, "A dataset of inter-county distances along the real-world highway and railway networks in the contiguous United States," published in Scientific Data, a Nature Portfolio journal, introduces a dataset with more than 15.2 million county-to-county distance records across the contiguous United States. It gives researchers a more accurate foundation for studying the cost of moving goods.

Deniz Berfin Karakoc is an assistant professor of industrial engineering in the School of Computing and Augmented Intelligence, part of the Ira A. Fulton Schools of Engineering at ASU. She studies large transportation networks and how to move food and other essential commodities more efficiently.

“A straight line can tell you how close two counties are geographically, but it cannot tell you how far goods need to travel along highways or railways,” Karakoc says. “We wanted to give researchers a consistent way to measure those network distances at the county scale.”

That conclusion comes as Austin, Texas-based Magnus reported that the U.S. average retail diesel price rose to $6.29 a gallon in September, up $0.78 from the end of August and 68% above September 2025 levels. Those numbers came from the firm’s “September 2026 Diesel Fuel Snapshot” report.

In fact, September 2026 marked the highest monthly average in U.S. Energy Information Administration (EIA) weekly data dating back to 1994. All four September weeks priced above $5.00, bringing the 2026 total to 25 weeks above that threshold.

The speed of the price increase from August to September matters most for carriers whose surcharge programs reset monthly or are based on prior-period averages. When prices rise this fast, a surcharge priced off last month’s average trails what trucks are actually paying at the pump, and the difference comes out of carrier margin on every load until the surcharge table catches up. At 6.5 miles per gallon, a surcharge that trails the pump by $0.78 a gallon costs a carrier 12 cents a mile, or about $300 per truck on a 2,500-mile week.

“A fuel surcharge is supposed to make fuel neutral, it’s not supposed to be a profit builder for either side or a huge cost burden for the carrier,” said Matt Cartwright, founder and CEO of Magnus Technologies. “September showed how fast that balance breaks when diesel sets a new record hitting above $6.00. If your surcharge resets based off of last month’s price, you’re paying September’s price at the pump while only getting paid on August’s price. The fix is to re-rate against the published index every week, so both sides know what’s reasonable.”

Instead of waiting for fuel prices to normalize, leading companies are taking four steps to help counter the impact of the surge in diesel fuel costs.

Take control of fuel surcharges. Shippers can establish their own surcharge schedules in carrier contracts, pegged to the US Energy Information Administration’s published weekly diesel prices. This creates a more predictable, auditable reimbursement mechanism. Companies that use carriers’ surcharge tables can negotiate limits on how frequently those tables change and how large adjustments can be.

Shift eligible freight to rail. Rail costs significantly less per mile than truckload shipping, and one railcar can carry the equivalent of four full truckloads. It is slower and less flexible on delivery windows, so it’s most appropriate for nonperishable, time-tolerant freight, not just-in-time or temperature-sensitive goods. Better planning matters, too: Avoiding expedited shipments where possible, particularly premium air freight, can eliminate a significant source of unnecessary expense.

Reduce wasted miles and fuel consumption. Leaders work with carriers to find loads for trucks that would otherwise return empty, reducing both empty miles and fuel consumption. Companies operating private or dedicated fleets can also use telematics to identify excessive idling, inefficient routes, driving behaviors, and maintenance issues that increase fuel use. Individually, these actions may appear incremental, but when implemented systematically, they can produce sustained fuel savings.

Manage inbound freight as rigorously as outbound. Suppliers may seek price increases as their transportation costs rise. Procurement teams need transparency into the freight component of supplier pricing so they can distinguish legitimate cost pressure from broader price increases. Where scale permits, companies can also evaluate whether managing inbound transportation directly through their own logistics organization creates greater leverage.

Diesel volatility is a reminder that freight should be managed as a strategic cost, not simply a transportation expense. Companies that understand their exposure, establish disciplined surcharge mechanisms, and continuously optimize their networks will be better positioned to protect margins through the current spike and whatever comes next.

Beyond driving directions...For anyone accustomed to getting driving directions on a phone, that might sound like a problem already solved. Commercial routing tools can calculate trips between specific addresses. But studying transportation across thousands of counties requires a standardized dataset that supports comparisons across an entire country and across transportation modes.

Existing freight information often covers regions too large to support detailed county-level analysis. Without suitable distance data, researchers sometimes rely on calculations based on latitude and longitude. Those approximations capture geographic separation but cannot follow a highway around an obstacle or trace the connections in a rail network.

Organizing distances by county allows researchers to pair the dataset with existing estimates of goods moving between counties to better assess transportation costs. 

Karakoc, along with industrial engineering graduate student Yongxin Cai and data science graduate student Xinyan Li, started with federal transportation maps and county boundaries. They converted highway and railway segments into networks of nodes and links, then calculated the shortest paths between representative locations within counties.

Think of a vast collection of connected line segments. Each segment carries a distance. The task is to find the combination connecting two locations with the smallest total mileage.

The resulting dataset includes highway distances for 2,863 counties and railway distances for 2,649. It is publicly available, giving other researchers a foundation they can combine with information about commodities, shipment volumes, fuel consumption or transportation costs.

The dataset could help researchers explore how fuel prices affect the cost of moving goods. Combined with information about fuel efficiency and shipment volumes, these distances could offer a clearer picture of how transportation costs vary across suppliers, locations and routes.

From miles to making decisions...Consider a hypothetical food distributor comparing two suppliers. One might appear closer in a straight-line calculation but require a longer highway trip. Establishing that difference would be one step toward comparing transportation costs. Shipment size, vehicle efficiency, delivery schedules and other operating conditions would determine the rest.

“This dataset provides a foundation for asking more detailed questions about transportation costs, infrastructure and supply chains,” Karakoc says. “By representing the distances along actual networks, we can help future analyses better reflect the geography that freight has to navigate.”

The researchers checked their method against broader freight-flow information and compared samples of county-to-county distances with independent road and rail routing systems. Those comparisons showed strong overall agreement, although individual routes differed. The data are intended as a benchmark for broad freight analysis, with limits that matter for practical use.

A shortest path is not necessarily the fastest or cheapest route. The dataset does not incorporate all directional restrictions or operating constraints. Its representative county locations are not individual warehouses, highway interchanges or freight terminals. And a rail connection on a map does not, by itself, establish that a particular shipment can use it.

Those details would need to enter any analysis intended to guide a real shipment.

Ross Maciejewski, director of the School of Computing and Augmented Intelligence, says that the value of the work extends beyond examining current fuel-price spikes.

“This publicly available dataset gives researchers a shared starting point for studying transportation costs, emissions and supply-chain disruptions,” Maciejewski says. “Instead of building their own distance estimates, they can focus on what those distances mean for the movement of food, medicine and other essential goods.”

Where should a company build a warehouse? Which suppliers are best positioned to serve it? Where would a new transportation connection help? 

Distance informs each of those decisions. By measuring it along actual roads and rails, Karakoc’s new dataset could help researchers evaluate the options with a clearer understanding of the journeys involved.

When diesel prices rise, every freight mile matters... As diesel prices soar, efficiency in freight transport becomes a matter of financial survival. In October 2026, the national average price for diesel in the United States reached approximately $6.32 per gallon—a drastic jump from the $3.62 recorded a year earlier. This sudden increase means that every mile traveled has a direct impact on the profit margins of both trucking companies and independent owner-operators.

The impact on supply chains... Rising fuel costs trigger a ripple effect, driving up the price of everything from basic commodities to industrial components:

• Mismatches in fuel subsidies: Surcharge programs often rely on averages from the previous month. When diesel prices climb rapidly, carriers must cover the difference out of their own pockets until the rate schedules are updated.

• Squeezed margins: With diesel hovering near $6.30 per gallon, fuel costs can consume nearly half of an independent driver’s gross earnings.

• Empty miles: Moving trucks without cargo—known as "empty miles"—becomes an unsustainable loss, as the vehicle continues to consume expensive fuel without generating any revenue.

New approaches and technologies...To navigate this brutal macroeconomic landscape, the logistics sector and the academic community are adopting new strategies:

• More realistic routing: Researchers at Arizona State University (ASU) have developed an advanced method for estimating freight costs by calculating the actual distances along the highways and railways used, moving away from the traditional approach of measuring straight-line distances between two points. • Efficiency-focused training: Commercial driver training programs are revamping their curricula with a strong emphasis on smart routing and the reduction of engine idling time.

• Market visibility: According to logistics experts at Fare Lanes, having real-time visibility into rate fluctuations is crucial for brokers and shippers to recalculate costs without disrupting supply chains.