Road freight crime has halved since 2001, according to TruckPol, a division of the Metropolitan Police.
TruckPol found that the number of incidents reported fell between July and September this year to 437 from 876 for the same period in 2001.
The biggest falls were in thefts of hauliers and in 'jump up' crime, where cargo is stolen while the vehicle is stationary.
But a spokesman for vehicle security network Eurowatch said that he did not expect the hard insurance premiums in this area to fall.
"There are still problems with reporting these incidents," he said. "Insurers will wait and see."