Greenwich Mean Time

Another name for Zulu Time. GMT/ZT is used on shipping contracts, and some tariffs, when a shipment either needs to be delivered, or is guaranteed to be delivered, by a certain time.

Gross Cargo Weight

Total weight of lading (cargo), including blocking, bracing and pallets.

Gross Ton

A unit of measure equal to 2,240 pounds.

Gross Ton-mile

The movement of the combined weight of cars and their contents a distance of one mile.

Gross Tonnage

Applies to vessels, not to cargo; determined by dividing the vessel’s interior spaces by 100 cubic feet. A vessel ton is 100 cubic feet.


Abbreviation for Gross Vehicle Weight, meaning the combined weight of the vehicle and freight.

Gross Weight

Entire weight of goods, packaging, and freight car or container, ready for shipment. Generally, 80,000 pounds is the maximum weight for container, cargo, and tractor for highway transport and 272,000 pounds is the maximum for cargo, and freight car (4 axle cars) for railroad transport.


An abbreviation for – Hazardous Material.

Hazardous Commodities

Materials as defined by the DOT in the Code of Federal Regulations (49 CFR) as hazardous materials, hazardous wastes and hazardous substances.

Head Haul

The opposite of backhaul.

Heavy Weight

Loaded truck and trailer.


Household goods.

Highway Master

Satellite system used to communicate with the driver and track the location of a tractor and his load.

Hopper Bottom

Trailer that can be unloaded through the bottom, most commonly used to haul grain.


Hours of service – the number of hours in a 24-hour period the DOT allows a driver to operate his/her truck.

Hub Center

Any designated facility for interchange of intermodal vehicles for ramping / de-ramping or vehicle delivery or pickup.