The rule was extended in 1994 to include all passenger vehicles up to a gross weight rating of 6,000 pounds. (iihs.org)
For purposes of these statistics, a large truck was defined as a truck with a gross vehicle weight rating greater than 10,000 pounds. (cochranfirm.com)
The larger leaf - spring design supports increased rear gross axle weight ratings across the board. (topspeed.com)