Truck drivers, their employers, and the public bear the costs of large truck crashes. Prior research finds that truck drivers tend to have fewer crashes when they are paid more, yet much of the U.S. industry operates with low pay and high turnover. We use carrier‐level safety records and regional earnings information covering more than 40,000 carriers to show that the pay‐safety relationship weakens during periods of labor market slack or heightened cost pressures. These findings suggest that upstream economic factors influence trucking safety and that recent economic regulation of trucking in other countries may inform U.S. policy.