US diesel prices near record levels are intensifying cost pressures on schools, farms, small businesses and freight operators, while trucking and cargo-shipping rates have climbed to their highest levels since Covid-era supply-chain disruptions by some measures. AAA said diesel reached a record $6.53 a gallon on Sept. 22 and had risen 77% over the prior year. The national average was about $6.50 a gallon on Friday, compared with $3.69 a year earlier, while the Energy Information Administration reported on-highway diesel at $6.529 a gallon on Sept. 21. Record diesel prices are a major driver of higher transport costs, alongside other freight-market pressures. Trucking, rail and ocean-shipping expenses are crimping company margins and could feed through to prices for consumer goods including clothing and food. Economists warn that sustained increases in fuel and logistics costs could reinforce inflation and support expectations for higher US interest rates.