Trucking spot market rates across the United States have surged unexpectedly overnight, despite weak volumes and low tender rejections, reports New York's FreightWaves.

SONAR's spot market heat map showed a sharp rise in rates nationwide, with no corresponding increase in tender volumes or rejection rates, which remain at 5.5 per cent.

Typically, rising spot rates are linked to higher demand and increased tender rejections. However, current data suggests the surge is driven by supply-side constraints.

FreightWaves conducted market checks with major carriers and brokers, confirming the unusual trend of low volumes paired with rising rates.

Industry observers are now questioning whether this is a short-term anomaly or the beginning of a broader market squeeze.