SPIF Vehicle	Description	Schematic
#1	Fixed-Axle Semi-Trailer:- single axle - tandem axle - tridem axle
#2	Self-Steer Triaxle Semi-Trailer
#3	Self-Steer Quad Semi-Trailer
#4	5-Axle Self-Steer Semi-Trailer (1-3-1)
#5	5-Axle Self-Steer Semi-Trailer (1-1-3)
#6	6-Axle Self-Steer Semi-Trailer (1-4-1)
#7	6-Axle Self-Steer Semi-Trailer (1-1-4)
#8	Tri-Drive Tractor Fixed Axle Semi-Trailer
#9	Tri-Drive Tractor Self-Steer Triaxle Semi-Trailer
#10	Tri-Drive Tractor Self-Steer Quad Semi-Trailer
#11	A-Train Double
#12	B-Train Double
#13	C-Train Double

Non-SPIF Allowable Gross Weight (AGVW) Reductions
(Move down left column to find vehicle - then read across row)

Vehicle	July 1 2002	Jan 1 2003	Jan 1 2006	Jan 1 2011	Jan 1 2016	Jan 1 2021
SPIF vehicles	Aggregate AGVW calculation and 1500 kg reduction no longer apply to SPIF vehicles	exempt from AGVW reductions listed below	exempt from AGVW reductions listed below	exempt from AGVW reductions listed below	exempt from AGVW reductions listed below	exempt from AGVW reductions listed below
Non-SPIF end-dump and open-top hopper dump semi-trailers		4500 kg** AGVW reduction if built after 2002		4500 kg** AGVW reduction also applies to vehicles built prior to 20031
Non-SPIF specialized2 tankers with 3 or less axles						4500 kg AGVW reduction
Non-SPIF non-specialized3 tankers with 3 or less axles			3000 kg AGVW reduction			AGVW reduction increases to 4500 kg
All other non-SPIF semi-trailers with 3 or less axles			3000 kg AGVW reduction	AGVW reduction increases to 4500 kg
Non-SPIF semi-trailers with 4 or more axles, and non-SPIF double trailers			4500 kg*** AGVW reduction if built after 2005		4500 kg*** AGVW reduction also applies to vehicles built prior to 20064

** Reduction is 9,000 kg if combination has two or more deployed lift-axles5 ***Reduction is 9,000 kg if combination has two or more deployed lift-axles, or is an A or C-train double.

1. Starting in 2011, dump semi-trailers built prior to 2003 are eligible for special annual permits exempting them from this weight reduction until they reach 15 years from year of manufacture (20 years for open hoppers).

2. Specialized Tankers include single semi-trailers with 3 or less axles that are: a carbon dioxide tank semi-trailer; a cryogenic tank semi-trailer; or a tag-axle tank semi-trailer.

3. Non-Specialized Tankers include single semi-trailers with 3 or less axles that are liquid or dry-bulk tankers other than those listed above as Specialized Tankers.

4. Starting in 2016, non-dump semi-trailers with 4 or more axles and all double trailers built prior to 2006 are eligible for special annual permits exempting them from this weight reduction until they reach 15 years from year of manufacture (20 years for liquid or dry-bulk tankers).

5. Definition of lift-axle includes any axle that is equipped with a device for altering the weight transmitted to the highway surface, or that is able to lift its tires from contact with that surface.