Trucking Market: Volumes UP, Diesel Soaring. Is Peak Here?

The freight market is showing its first signs of year-over-year growth in 42 months. Dive into this week’s Sonar update as we break down rising diesel prices, the latest spot rates, and how shipping volumes are signaling a fragile but shifting market as peak season approaches. Understand the key numbers impacting your operations and what to expect next.

Diesel prices surged to $6.26 per gallon to start the week of Sept. 16, a 33-cent jump in a single week from $5.936 on Sept. 8, according to FreightWaves’ Diesel Transaction Spot (DTS) index — a figure that updates daily and has already climbed above the U.S. Department of Energy’s latest weekly read of $6.28. The spike puts diesel 15% above last month’s $5.45 per gallon and 68% higher than the $3.72 recorded at the same point last year, compressing carrier margins even as freight volumes begin to recover.

The fuel surge matters because spot rates are not keeping pace. The Sonar National Truckload Index (NTI) seven-day average dipped 2 cents per mile week over week, falling from $3.44 to $3.42 as of Sept. 16. Despite the slight retreat, the NTI remains 3% above last month and 47% above last year’s level — a wide spread that underscores how much of carriers’ nominal rate gains are being consumed by fuel costs.

“Spot rates are not rising quickly enough to keep up with the increase in fuel costs, but are still strong — certainly significantly higher than this time last year and continuing to rise month over month,” said Julie Van de Kamp.

On the volume side, the Cass Freight Index shipments component posted a 2.1% year-over-year increase in August — the first positive reading after 42 consecutive months of year-over-year declines. Van de Kamp called it “an exciting number,” framing it as early evidence of a market inflection even as she cautioned that freight demand is expected to remain “relatively muted” given moderate consumer spending.

The Sonar Truckload Volume Index (STVI) showed a post-Labor Day volume spike, with volumes running 14% above the same week last year. Van de Kamp noted the comparison is partly distorted because Labor Day fell a week earlier in the prior year, creating a similar post-holiday surge in 2021’s data. Inbound ocean volumes are also firming, with the IOTI index tracking roughly 9% above year-ago levels, a signal that restocking activity — and tariff-related purchasing — may be adding incremental freight.

Capacity remains the defining story. Tender rejections held at 14% compared to just 5.5% at the same point last year, indicating that carriers still have meaningful leverage to decline loads. Van de Kamp described the current environment as a “fragile market” and said she expects peak season to be “more seasonally normal” than the outsized peaks of recent years — present but elongated rather than sharp.

“We expect rates to remain strong, but freight demand is expected to remain relatively muted based on what seems to be kind of moderate consumer spending,” Van de Kamp said, summing up a market where the ceiling on rate gains may be set more by wallets than by trucks.

• Diesel jumped 33 cents in one week to $6.26/gallon, now 68% above year-ago levels, while spot rates fell slightly to $3.42/mile.
• August Cass Freight Index shipments rose 2.1% year over year — the first gain after 42 straight months of declines.
• Tender rejections sit at 14% vs. 5.5% a year ago, keeping the market capacity-constrained heading into a likely muted peak season.

This Summary is generated thanks to a transcription of the interview, for the full interview please enjoy the video above.