More than a half of all goods vehicles stopped at police road checks were found to be breaking the law.
Officers from Dorset Police stopped 60 vehicles on the A31 at Ashley Heath, near Ringwood, last Thursday. Thirty-one were found to be defective.
Eleven goods vehicles were in such a bad state they were taken off the roads straight away.
The defective vehicles had problems with tyres, brakes, lights and leaking fuel and oil.
Ch Insp Rick Dowell said: "Once again, specialist road policing officers have detected a significant number of serious defects, which all had the potential to result in collisions.
"And the chance of serious injury is always greater when a large goods vehicle is involved."