What's the difference between transportation-specific per diem and the High-Low Substantiation Method?

Transportation-specific per diem is a fixed daily allowance ($80 or $86 depending on geography) that applies exclusively to workers in the transportation industry. The High-Low Substantiation Method is a broader IRS approach applicable to all industries that simplifies expense tracking by designating certain locations as high-cost areas ($329 effective FY2026) and all others as standard areas ($230). Companies choose which method best fits their compliance and cost management strategy.

Why did transportation per diem rates stay flat while High-Low rates increased?

The article does not explain the IRS's rationale, but the stability in transportation-specific rates likely reflects regulatory acknowledgment of trucking's standardized expense environment and driver advocacy. High-Low increases suggest the IRS is adjusting for cost-of-living changes in designated high-cost localities, which shift annually based on economic conditions.

How do high-cost area designations work, and how often do they change?

The IRS classifies certain locations as high-cost for specific periods based on seasonal or economic factors. For example, Gulf Shores, Alabama is high-cost only June 1–July 31, while New York City qualifies year-round. Panama City, Florida previously held the designation but was removed in the latest IRS release. Companies must check the official IRS list annually to ensure accurate reimbursement rates.

What operational impact should carriers expect from these rate changes?

Carriers using transportation-specific per diem face no new cost pressure. However, those using High-Low Substantiation must budget for 2–3% increases in per diem reimbursements, which affects payroll, driver retention strategies, and competitive compensation positioning, particularly in high-cost markets.

Are there compliance risks associated with selecting the wrong per diem method?

Yes. Carriers must ensure their chosen method (transportation-specific or High-Low) aligns with IRS guidelines and their operational structure. Misapplication can trigger audit exposure and back-payment liability. The article emphasizes that High-Low's simplified locality classification reduces complexity but requires annual updates to the IRS's designated high-cost area list.

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IRS Per Diem Rates: Stability for Truckers, Increases for High-Cost Areas

Sep 27, 2026

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The signal

The Internal Revenue Service announced fiscal year 2026 per diem rates with divergent outcomes for the trucking industry. S. travel and $86 for outside travel, providing stability for drivers using this method to deduct meal and incidental expenses. However, companies employing the High-Low Substantiation Method—a broader approach applicable across all industries, not just trucking—will see increases: high-cost area designations rise from $319 to $329, while other areas move from $225 to $230. This mixed outcome reflects the IRS's approach to managing employee expense reimbursement across the economy.

S. locations into two tiers. These designations are neither static nor limited to obvious metropolitan centers; Gulf Shores, Alabama qualifies during summer months, while Aspen, Colorado carries the designation nearly year-round. This dynamic classification system requires carriers and third-party employers to maintain current IRS guidance. For supply chain professionals, the implications are nuanced.

2% increases respectively. These changes cascade through payroll, reimbursement processes, and compensation models, particularly for companies with large over-the-road fleets. The stability of transportation-specific rates suggests regulatory recognition of trucking's unique operational context, while High-Low increases signal inflationary pressures in living costs across designated regions.

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What if your carrier switches from transportation-specific to High-Low per diem for driver compensation?

Model the cost impact of migrating a fleet of 500 over-the-road drivers from the stable $80/day transportation-specific per diem to the High-Low method with rates of $329 for high-cost and $230 for standard areas. Assume 60% of driver days occur in designated high-cost locations. Calculate annual payroll impact, reimbursement policy changes, and regional competitiveness effects.

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What if high-cost area designations expand or shift unexpectedly next year?

Stress-test the reimbursement budget by modeling scenarios where an additional 15–25% of driver routes fall into high-cost area classifications due to IRS policy updates. Assess how this would affect payroll predictability, freight pricing strategies, and driver retention in affected regions.

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