A port's investigation into how a 40ft (12m) container was lowered onto a lorry's cab and trapped the driver inside has concluded the vehicle was "incorrectly parked".
The incident happened at Felixstowe in Suffolk on 23 April.
The man was cut free by fire crews and was later discharged from hospital.
A spokesman for the Port of Felixstowe said "the order in which cranes handle vehicles" had been changed to prevent any repetition.
The spokesman said the report had been submitted to the Health & Safety Executive (HSE).
"The report found that the haulier was incorrectly parked and was not seen by the crane driver," he added.
"To avoid a repetition, the order in which cranes handle vehicles has been changed, improved training aids are being provided for hauliers, and two new cameras are being installed which significantly improve the view for the crane driver.
"These measures have been agreed with the HSE."