Diesel jumped $0.10 per gallon in a single week to just under $6.57 as of Monday, Sept. 28, while all-in truckload spot rates rose only $0.02 per mile over the same period. That widening gap is compressing margins for trucking companies and putting a premium on load utilization heading into peak season.

The National Truckload Index sits 5.2% above its level from last month, when it stood at $3.28 per mile. Diesel, by contrast, is 16.5% higher than a month ago. The divergence shows up clearly in the spread between the DTS fuel index and the NTI spot rate heading into late September, and the trend shows no sign of reversing near-term, said Julie Van de Kamp.

"Fuel is rising more quickly than spot rates," Van de Kamp said. "So we'll continue to see that pressure on trucking companies."

The mechanics of the squeeze matter for shippers and carriers alike. Fuel surcharges offset higher diesel costs on contracted freight, but carriers absorb the full cost of elevated fuel prices on empty miles. That makes deadhead reduction the critical lever for operators in the current environment — every repositioning mile now carries a materially higher cost than it did a month ago.

"There are so many reasons that there's still pressure on trucking companies and pulling demand capacity out of the market while demand has remained weak," Van de Kamp said.

Regulatory pressure tightens supply

On the capacity side, Van de Kamp pointed to a recent conversation with Jim Filter, CEO of Schneider, who echoed concerns about regulatory actions tightening available supply. Crackdowns on non-domiciled CDLs and the shutdown of driving schools with inadequate training standards are raising barriers to entry for new carriers and drivers. The result: capacity is contracting independent of demand signals, a dynamic that supports rates even in a soft freight economy.

Demand stays the wildcard

Demand itself remains the market's biggest question mark. The Sonar Truckload Volume Index has held relatively flat through 2024, with two key freight drivers — automotive and housing — still running soft. Discount retail has performed well, but weak consumer sentiment is keeping overall freight demand muted heading into peak season.

Tender rejections are holding around 14%, a level Van de Kamp described as healthy and well above year-ago readings. That gives carriers continued negotiating leverage with shippers despite the muted demand backdrop — a shift in the shipper-carrier balance that has defined 2024.

Elongated, stable peak ahead

Looking ahead through peak, Van de Kamp projected "an elongated and stable peak" rather than a sharp seasonal surge. Contract rates should continue to climb. Intermodal should maintain momentum as shippers convert loads for cost savings. Inbound import volumes remain solid.

Absent a meaningful recovery in automotive or housing, or a shift in consumer sentiment, the freight market appears set for more of the same: tight capacity, stable-to-rising rates, and margin pressure concentrated at the fuel line.