72116342_Grand_Theft_Wiki__the_GTA_wiki__Description
[Ability] Heavy [Code] Heavy [Description] 
Means that the car can push and ram other vehicles out of the way very easily, without the car losing speed or turning in different directions. However, the Heavy property will not shield against damage, and the car will receive double damage when hitting cars and other objects.
Difference between revisions of "Special Vehicles" - Grand Theft Wiki, the GTA wiki