The U.S. freight market exhibited weakening growth momentum in September as port congestion, semiconductor shortages, and hurricane disruptions created a perfect storm of logistical challenges. The latest Cass Freight Index report reveals that while both shipment volumes and freight expenditures continued to grow, the pace of expansion has slowed significantly. Widely regarded as a bellwether for the transportation industry, the index's fluctuations often presage major turning points in the American freight market.
Sluggish Shipment Growth: Multiple Headwinds Constrain Recovery
The Cass Freight Index registered 1.184 in September, representing a mere 0.6% year-over-year increase—a stark contrast to August's robust 12.3% growth. On a monthly basis, September volumes declined 4.1% from August, with the seasonally adjusted drop reaching 4.9%. Tim Denoyer, Vice President and Senior Analyst at ACT Research, noted that September's weak performance aligns with other economic indicators including rail freight volumes and employment data. Hurricane Ida's impact further disrupted supply chains during the month.
While these factors might suggest a potential fourth-quarter rebound, Denoyer cautioned that the global semiconductor shortage—which worsened in September—will likely prolong the recovery timeline. The bottleneck at North American ports, where container ships remain anchored awaiting berths, continues to severely constrain freight capacity. Although some improvement in rail network congestion has been observed, Denoyer anticipates intermodal freight volumes will face ongoing constraints from chassis shortages in the coming months.
Freight Expenditure Growth Moderates: Elevated Rates May Persist
The September freight expenditures index reached 3.818, marking a 32.2% annual increase—down from August's 42.2% surge. Month-over-month, expenditures dipped 0.4% (2.5% seasonally adjusted). Denoyer projects that following normal seasonal patterns, the Cass Expenditures Index would finish 2021 with 34% annual growth, following 2020's 7% decline and 2019's flat performance.
The 2.5% seasonally adjusted decline between August and September primarily reflects the combination of lower volumes and higher rates. Notably, compared to two years ago, September shipments show a cumulative 33.8% increase—a figure Denoyer attributes largely to rate inflation rather than volume growth, as actual shipment counts have slightly decreased.
Analyst Perspective: Capacity Constraints Meet Demand-Side Challenges
Transportation analysts uniformly identify dual pressures facing the U.S. freight market: persistent capacity bottlenecks and evolving demand-side challenges. On the supply side, port congestion, equipment shortages, and driver scarcity continue limiting available capacity. Meanwhile, global supply chain disruptions and semiconductor shortages have slowed manufacturing output, subsequently dampening freight demand. Shifting consumer spending patterns have additionally reshaped freight mix requirements.
Port Congestion: The Supply Chain Chokepoint
North American port congestion remains the freight sector's most pressing challenge. Backlogs of container ships awaiting berths create cargo pileups that cripple supply chain efficiency. The congestion stems from multiple factors including dockworker shortages, inadequate trucking capacity, and rail network limitations. Resolution requires coordinated efforts across stakeholders—increasing dockworkers, improving terminal productivity, and enhancing rail infrastructure.
Chassis Shortages: The Intermodal Bottleneck
The critical chassis shortage—the wheeled frames that move containers between ports and inland destinations—has become a major obstacle for intermodal freight. Production shortfalls, maintenance backlogs, and uneven equipment distribution all contribute to the scarcity. Solutions must address production increases, repair turnaround times, and optimized allocation systems.
Driver Shortages: The Trucking Sector's Chronic Weakness
The perennial truck driver shortage has reached crisis levels, exacerbated by demanding working conditions, stagnant wages, and an aging workforce. The deficit reduces highway capacity, elevates rates, and extends delivery times. Meaningful improvement requires enhanced working conditions, competitive compensation, and renewed recruitment efforts targeting younger demographics.
Semiconductor Scarcity: Manufacturing's Achilles' Heel
Global chip shortages continue disrupting automotive and electronics production, subsequently depressing freight demand. Pandemic-related factory closures, surging demand, and geopolitical factors all contribute to the shortage. Resolution depends on expanded production capacity, optimized inventory management, and strengthened international cooperation.
Consumer Spending Shifts: Reshaping Freight Demand
The pandemic-driven shift from services to goods consumption has fundamentally altered freight patterns, while e-commerce growth has amplified parcel delivery needs. These changes compel freight operators to adapt their business models to evolving market realities.
Market Outlook: Challenges and Opportunities Ahead
Despite current headwinds, the U.S. freight market retains significant growth potential as economic recovery progresses and infrastructure investments materialize. Technological innovations—including autonomous trucks, delivery drones, and IoT solutions—promise to enhance efficiency and reduce costs across the transportation network.
Conclusion: Cautious Optimism Warranted
The September Cass Freight Index signals moderating growth amid persistent capacity constraints and demand volatility. Near-term challenges—particularly port congestion and equipment shortages—will likely persist. However, long-term fundamentals remain favorable, with economic expansion and technological advancement expected to drive future opportunities. Market participants should maintain vigilant monitoring of industry indicators while preparing operational adjustments to navigate evolving conditions.