INFORMATION / THE IRP
WHAT IS AN APPORTIONED LICENSE PLATE ?

APPORTIONED license plates are used by interstate vehicles, usually trucks, semi-tractors, or buses.
When a vehicle has APPORTIONED plates on it, it pays road taxes to all the states it travels through - in proportion to how much of the time the truck is actually in that state.
Thus, the tax fees are split up, or "apportioned", between the states where the vehicle travels.

This way, the vehicle does not have to carry a license plate from each state it goes through ... the only plate required is the APPORTIONED plate from the vehicle's home state.
Before these plates came along, interstate vehicles were required to have one license plate from each state it drove through - and sometimes this could be a lot of plates !!
WHAT IS THE IRP ?

The IRP (International Registration Plan) was formed in 1973 to be "an agreement between the participating jurisdictions which regulated the payment and apportionment of fees".
In other words, it's a pact between the states of the USA and the provinces of Canada which allows for interstate vehicles to easily drive through them all.
Learn about the history of the IRP here.

Today, all of the lower 48 states, the District of Columbia, and the 10 Canadian provinces are members of the IRP.
This means that they all issue either APPORTIONED or PRORATE (PRP) plates for interstate or inter-province vehicles.

Alaska used to issue APPORTIONED plates, but it stopped in 1979.   Hawaii never has, and more than likely, never will.   Neither Alaska or Hawaii are currently in the IRP.
The three Canadian territories - Yukon, NWT, and Nunavut - are not in the IRP either, and they do not issue APPORTIONED plates.

Several jurisdictions also previously issued APPORTIONED plates for trailers as well - but the last state which required apportioning of trailers (California), dropped the requirement in 2001.
Now, APPORTIONED trailer plates are being replaced by "Permanent" trailer plates in many states, but some still use the APPORTIONED designation.

APPORTIONED plates have been issued to trucks, tractors, trailers, buses, wreckers, and farm vehicles.


This is a commemorative plate from the IRP convention in 2008.

(From my collection.)
Below is a list of the current members of the IRP.

Their date of entry is listed, along with the year on the first plates to use the APPORTIONED caption (or APP, etc.).
Some Canadian jurisdictions have never used the word APPORTIONED, and currently Idaho and North Dakota use "PRP".

Notice the first plate dates - some states issued APPORTIONED plates before official entry into the IRP - for example, Texas and Tennessee had 1973 plates !

 STATE/PROVINCEENTERED INTO IRPFIRST APPORTIONED PLATE
 MissouriJanuary 1, 1974 1974
 TennesseeMarch 1, 1974 1973
 TexasApril 1, 1974 1973
 KentuckyApril 1, 1974 1975
 ColoradoJanuary 1, 1975 1975
 AlbertaJanuary 1, 1975 1976
 MinnesotaJanuary 1, 1975 1976
 NebraskaJanuary 1, 1975 1975
 OregonJanuary 1, 1975 1975
 South DakotaJanuary 1, 1975 1976
 UtahJanuary 1, 1975 1976
 VirginiaMarch 1, 1975 1976
 MississippiNovember 1, 1975 1976
 IdahoJanuary 1, 1976 1976
 MontanaJanuary 1, 1976 1977
 WyomingJanuary 1, 1976 1975
 LouisianaApril 1, 1976 1975
 Alaskac.1976 (withdrew 1979) 1976
 ArkansasJuly 1, 1976 1977
 IllinoisJanuary 1, 1977 1977
 North CarolinaJanuary 1, 1977 1977
 IowaJanuary 1, 1978 1978
 OklahomaJanuary 1, 1978 1978
 WisconsinJanuary 1, 1978 1978
 AlabamaOctober 1, 1980 1981
 ArizonaJanuary 1, 1981 1980
 KansasJanuary 1, 1981 1980
 North DakotaJanuary 1, 1981 1981
 PennsylvaniaJune 1, 1983 1983
 CaliforniaJanuary 1, 1985 1982
 MichiganMarch 1, 1985 c.1985
 ConnecticutMay 1, 1985 c.1987
 South CarolinaJanuary 1, 1986 1986
 West VirginiaJuly 1, 1986 c.1985
 FloridaDecember 1, 1986 1987
 IndianaMarch 1, 1987 1988
 WashingtonJanuary 1, 1988 1988
 MarylandMay 1, 1988 1989
 VermontMay 1, 1988 1988
 New YorkMarch 1, 1989 1989
 New HampshireMay 1, 1989 1989
 New MexicoJanuary 1, 1990 1990
 GeorgiaJanuary 1, 1991 1991
 OhioJune 1, 1991 1992
 NevadaJanuary 1, 1992 1992
 MaineJuly 1, 1993 1993
 SaskatchewanOctober 1, 1993 c.1997
 MassachusettsJanuary 1, 1994 1994
 DelawareJanuary 1, 1995 1995
 British ColumbiaJanuary 1, 1996 1996
 New JerseyApril 1, 1996 1996
 Rhode IslandSeptember 1, 1996 1998
 District of ColumbiaApril 1, 19971999 ??
 ManitobaMarch 1, 2001 c.2000
 New BrunswickApril 1, 2001 "PRP" used
 Newfoundland & LabradorApril 1, 2001c.2004
 Nova ScotiaApril 1, 2001 c.2007
 OntarioApril 1, 2001 "PRP" used
 Prince Edward IslandApril 1, 2001"PRP" used
 QuebecApril 1, 2001 "IRP" used