Police detected 1,200 driving offences and issued fines totalling £25,000 after stopping more than 400 trucks in a large-scale road safety operation.
One foreign heavy goods vehicle worth £80,000 was impounded and drivers were found to be failing to correctly operate tachographs, in some cases exceeding the ten-hour limit by as much as eight hours.
Officers from Devon and Cornwall Police and the Vehicle and Operator Services Agency worked together on the three-week operation, which ended this month.
Operation Fatigue pulled over 400 goods vehicles on main roads, almost 180 of them operated by companies outside Great Britain.
The total amount in fines imposed by way of graduated fixed penalty notices exceeded £25,000.
Co-ordinator of the operation, Sgt Richard Gordon, from Camborne said: "Operations such as these send a clear message to rogue operators that we are out there, checking on the condition and use of goods vehicles and will prosecute and prohibit wherever appropriate."
VOSA Area Manager Andrew Sauerzapf said: seizure of vehicles was the "ultimate sanction".
"This has been a very positive and immediate effect on fair competition rules and road safety," he added.