Rick Kretschmer's License Plate Archives 

Regular trailers

From 1921 forward, all the way to 1953, regular trailer plates were consistently identified with a "T" serial prefix.  I don't know whether the "T" was small or full-sized during the first few years, but by the mid-1920s it was always smaller than the numeric digits. 

Although I've never seen any mention of this in any of my written sources, apparently from the 1926 example shown at left, trailer plates used the same riveted disks as did truck plates.  Trucks that had a gross vehicle weight of 2 tons or greater had small disks riveted to their plates indicating the number of tons.  The number on the disk could be 2 through 9, or "X", which apparently indicated 10 or more tons.  Since the 1926 trailer plate at left has a "2" on the disk, it would seem to be for a two ton trailer.  Trucks with lesser G.V.W.s did not get such disks, and so I assume that light trailers didn't, either.  I'm sorry I don't know the exact years that these disks were used for either trucks or trailers. 

"SR" trailers

This plate type was reportedly introduced on the 1942 base.  1942 and presumably 1945 bases had a small "T" prefix like regular trailers, with a stacked "S/R" suffix.  Beginning on the 1948 base, the "S/R" and the "T" switched positions, so the "S/R" was on the left and the "T" was on the right.  The meaning of the letters "SR" has been variously reported as "shuttle relay", "special rate", and "state roads"; in any event, its purpose is unknown.  Since similar "SR" plates were also issued to some truck tractors, it leads me to believe that "SR" trailer plates might only have been used on some semi-trailers. 

Regular trailers

By "regular", I mean trailers that are not issued any special type of trailer plate.  Regular trailers were assigned the serial formats 00-00-Gx (1954-1964), 0000-Gx (1965-1969), and 0000 Gx (1970).  Separators could be dashes, diamonds, or colons through 1969.  For regular trailers, the first letter in the serial was always "G", indiciating the vehicle class.  As with most non-passenger plate types, the expiration date (stamped on the plate 1957-1970) was April 30 rather than March 31 used for passenger vehicles. 

Dump trailers

I'm not sure what year this plate type started, but by the 1959 expiration plate, specific plates for trailers with dumping mechanisms were being issued.  This plate had the words Dump and Trlr running vertically down the left and right edges of the plate, respectively, with a four-digit serial number starting at 10-01.  It's a safe bet that this same design continued until the 1970 expiration plate, except that the serial separator was omitted starting with the 1965 expiration plate. 

"SR" trailers

I honestly don't know what "SR" stood for or meant.  I've seen explanations that it stood for "shuttle relay" or "special rate" or "state roads".  But even if any of these are correct, there still is no explanation for what these terms actually meant, or what the criteria was for being issued one of these plates rather than a regular trailer plate.  In any event, "SR" trailer plates were rather cryptic.  The serial consisted of a stacked S over R, followed by a four digit numeric serial, followed by the letter T, which is smaller than the numbers but larger than the stacked letters.  Thus, the format would be S/R00-00T.  I've only seen these plates with 1958 and earlier expiration years. 

Regular trailers

Regular trailers again used the 0000 xx format, with the first letter "G", indicating the vehicle class for trailers.  But late in the life of the 1971 base, trailer plates reached serial 9999 GZ, exhausting the format that had been used since the 1954 plates.  Although during 1954-1970, format 0000 Hx had signified a truck for hire plate, this format with a letter H had not been used on the 1971 base.  So, when the "G" series was exhausted, the MVA simply continued alphabetically and proceeded to issue "H" series plates to trailers.  They didn't get too far into the H series before the 1971 base was retired.  Plates started being made with serial dies from the upcoming red on white plates at the "HB" suffix.  The highest trailer serial I've seen on this base had an "HD" suffix. 

Dump trailers

I haven't seen a dump trailer plate on the 1971 base, but I have seen a document from the Maryland MVA that indicated that it had the legend Dump Trailer displayed horizontally with the words stacked one above the other on the left side of the plate, and a four-digit numeric serial occupying the center and right portions of the plate. 

Regular trailers

Trailers as well a number of other non-passenger classes were issued plates with serial format x 00000.  The letters assigned to trailers were A, B, C, and E.  (D was used for dealer plates.)  These letters had no hidden meaning; the serials were simply assigned consecutively through this range of letters.  The E series was only used on the 1981-1987 black and white base.  The word Trailer was embossed on the bottom center of the plates.  Trailers were not eligible to receive the optional Bicentennial or 350th Anniversary bases.  Semi-trailers were issued standard trailer plates unless they fell into one of the categories below. 

Dump trailers

Trailers with dumping mechanisms were assigned plates with the serial format DT 000.  The ALPCA archives reports that these plates bore the legend Dump Trl embossed at the bottom center, but I've seen a photo of a plate on the 1976 red on white base with the words Dump Trailer spelled out in full.  Possibly both legends were used. 

Farm trailers

During these years, trailers used for agricultural purposes received distinct plates.  Serial format was TR 000, and the legend Farm Trl was embossed at the bottom center. 

Fleet trailers, 1976-1993

Beginning in 1976, owners of trailer fleets were able to register their trailers for up to eight years at a time.  Trailers with long-term registrations were issued plates with the serial format 00000.  I don't believe that long-term registrations were only available for specific types of trailers, but in practice, I observed fleet trailer plates in use exclusively on semi-trailers. 

On the red-and-white base, fleet trailer plates were embossed with the cryptic legend Trl Apr 84 at the bottom center, which meant "Trailer, April 1984", the expiration date.  With the expiration date embossed, these plates did not use stickers, and they all expired in April 1984 regardless of the year of issuance. 

1992 fleet trailer sticker

On the black-on-white, all-embossed base, fleet trailer plates continued the serial format, but without an embossed expiration date; instead, a sticker was used to indicate the expiration.  Apparently, with the introduction of an expiraiton sticker, these plates were allowed to expire eight years from initial registration, rather than all at the same time.  The earliest year stickers were dated 1988, and the 1988 through 1993 expiration stickers used on this base, which would have been issued between 1980 and 1985, resembled the standard 1982 through 1986 year stickers with the state map outline that were issued during this same period. However, long-term trailer stickers were always white on red, and they did not contain a serial number.  Month stickers were not used on this base but the expiration month was always April.  Probably a disproportionate number of these had 1992 expirations, as they were issued in 1984 to replace the red-on-white plates with the embossed expiration date. 

Some of these black-on-white plates bore the legend Trailer while others had no legend; I haven't yet determined which came first or when the change occurred. 

Standard base trailer plates

Trailers were assigned serial format 000000G on the standard base, with the letter G indicating the vehicle class code for trailers.  With seven characters there was no room for a shield separator; there was also no longer an identifying legend at the bottom.  Special trailer types (dump trailers, farm trailers, and fleet trailers) that previously received distinct plates were merged with regular trailers on this base.  Beginning in 2005, at about serial number 854000G, the state's web site address was added along the bottom edge of the plate. 

After being issued for over 22 years, the 000000G format was exhausted in mid-2008.  Rather than just move the vehicle class letter to the beginning of the serial, as had been done for multi-purpose vehicle plates in the late 1990s, instead, an unexpected new serial format 00000TL was begun.  With only five variable digits rather than the previous six, this serial format won't last more than a few years before they'll have to come up with another one. 

(For fleet trailers with expirations between 1988 and 1993, please see the previous section, as these were issued on the painted, all-embossed black-on-white base through early 1986.) 

Between 1986 and 2007 or 2008, fleet trailers with eight year registrations have received normal trailer base plates with distinct month and year stickers.  The earliest issues of fleet registrations on this base were issued in 1986 and expired in 1994.  During this time, with 1994 through 2015 (and probably also 2016) expirations, both the month and year stickers have continued to always be colored white on red, like the 1992 sticker shown above.  In any event, these plates are easily identified because the month sticker bears the alphabetic month name (always April) rather than the month number used for all other types of Maryland license plates.  It's been reported that fleet trailer year stickers did not contain serial numbers until the 2007 sticker. 

Plate spotter Jeff Ellis reports that apparently beginning with the 2017 expiration sticker issued in 2009, fleet trailer year stickers are now colored black on white, just like all other year stickers. 

When Maryland joined the International Registration Plan (IRP) in 1988, it began issuing plates with the legend Apportioned to trailers and various types of trucks and buses that participated in the plan.  Apportioned trailer plates were assigned serials in the format 000*G00, where the letter G is constant and indicates the vehicle class.  Other letters were used for other apportioned vehicle types.  Apportioned trailer plates have been been discontinued for some time, but it's not clear exactly when this occurred.  They're not seen is use any longer.  Apportioned year stickers for 2005 were white on green rather than black on white used for most other plates, although it's uncertain whether apportioned trailer plates were still in use then. 

Special interest trailer plates

Light trailers could obtain the optional green-on-white first generation Treasure the Chesapeake base.  Trailer plates were issued in the serial format of G00*000 on this base; the highest observed serial is G08*297.  These plates are no longer issued, but remain valid with renewal stickers. 

Light trailers may now obtain the optional Our Farms, Our Future base and the black-on-blue second generation Treasure the Chesapeake base.  Trailers share the serial format A000000 with cars, taxis, trucks, and multi-purpose vehicles on the Our Farms base, but trailer serials are limited to the A900000 range.  New-style Chesapeake base trailer plates have serial format 00000G/A. 

On both the 1976 and 1981 bases, serial format was 00000 and the plates bore the embossed legend Spec Equip, which stood for "Special Equipment", or perhaps even "Special Mobile Equipment". 

Mobile equipment plates on the screened Maryland base follow the format of dealer and automotive business plates.  These plates have serial format 4E00000 and the screened legend Special Mobile Equipment at the bottom.  The word "special" in the legend seems rather unnecessary, since there is no regular, non-special mobile equipment plate category. 

Only single plates are issued.  Like dealer plates, they're not registered to specific vehicles, and can be freely moved from one piece of equipment to another, owned by the same business.  Thus, a business that had 20 pieces of mobile equipment, but only five drivers, might only need to obtain five license plates for their equipment.