A Pictorial History of Maryland License Plates
Trailer and Mobile Equipment Plates Dated 1915 to Present

Trailers

1915-1920 trailers

Trailer plates were apparently introduced in either 1915 or 1916. Early examples through 1919 were not embossed, and were noticeably different looking from passenger plates. They had the word "Trailer" across the top of the plate, and the abbreviation MD stacked over a two-digit year on either the left or right side of the plate, depending on the year. I don't know if these were were porcelain-coated or not. In 1920, embossed trailer plates were used, and the word "Trailer" was moved to the bottom of the plate.


1921-1953 trailers

• Regular trailers: From 1921 forward, all the way to 1953, 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.

Plate numbers observed - 1942 base: T15-073; 1948 base: T11-709, T29-711

• "S/R" 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 "S/R" has been variously reported as "shuttle relay", "special rate", and "state roads"; its purpose is unknown. Since S/R plates were also issued to some truck tractors, it leads me to believe that S/R trailer plates might only have been used on some semi-trailers.


1954-1970 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 vehicle plates, the expiration date (stamped on the plate 1957-1970) was 4-30 rather than 3-31 used for passenger vehicles.

• Dump trailers: I'm not sure what year this plate type started, but by the 1959 expiration plate, dump trailer plates 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.

• Farm trailers: No information available; such trailers were probably issued regular trailer plates during these years.

• "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. 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.


1971-1975 trailers

• 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 words "Dump" and "Trailer" displayed horizontally and 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.

• Farm trailers: No information available; such trailers were probably issued regular trailer plates during these years.


1976-1987 trailers

• 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 dealers.) 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 farming received distinct plates. Serial format was TR 000, and the legend "Farm Trl" was embossed at the bottom center.

• 1976-1993 long-term semi-trailers: Some semi-trailers were permitted to register for up to 8 years at a time. These trailers were issued plates with the serial format 00000. On the red and white base, these were embossed with the legend "Trl Apr 84" at the bottom, which meant "Trailer, April 1984", the expiraiton date. Apparently these were first issued in 1976. With the expiration date embossed, these plates did not use stickers, and all plates expired in April 1984 regardless of the year of issuance.

On the black on white embossed Maryland base, 8 year 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 8 years from initial registration, rather than all at the same time. The earliest year stickers were dated '89, and the '89 through '93 expiration stickers used on this base, which would have been issued 1981 through 1985, looked like the standard '82 through '86 year stickers with the state outline that were issued during this same period, except that long-term trailer stickers were always white on red (or white on pink depending on who you ask), and they did not contain a serial number. Month stickers were not used on this base but the expiration month was always April. Some of these plates bore the legend "Trailer" while others had no legend; I haven't yet determined which came first or when the change occurred.

1987-present trailers
Trailers and semi-trailers are assigned serial format 000000G on the standard base, with the letter G indicating the vehicle class. With seven characters there is no room for a shield separator; there is also no identifying legend at the bottom. Special trailers (dump trailers, farm trailers, and long-term semi-trailers) that previously received distinct plates were merged with regular trailers on this base. Standard trailer plates began appearing with the state's web site address at the bottom of the plate beginning in 2005. The cutoff point between the plain and web site versions occurred at about serial number 854000G.

When Maryland joined the apportioned vehicle program, it was required to issue plates bearing the word "Apportioned". Apportioned trailer plates are assigned serials in the format 000*G00, where the letter G is constant and indicates the vehicle class. (Other letters are used for other apportioned vehicle types.) It's been reported by one collector that apportioned trailer plates have been been discontinued, but the Maryland Motor Vehicle Administration still shows them on their web site. Apportioned year stickers for 2005 are white on green rather than black on white used for most other plates.

Long-term (8 year) semi-trailers receive normal trailer base plates but have distinct month and year stickers. Both the month and year stickers are always white on red in color, not white on pink as others have reported. 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. The earliest issues of this base were issued in 1986 and expired in 1994. Reportedly, the year stickers did not contain serial numbers until the '07 year sticker.

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.

Trailers may also obtain the optional "Our Farms, Our Future" base and the new 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.

Mobile Equipment - motorized and non-motorized

Off-road farm equipment such as tractors and combines are not required to be registered with the state, even when operated on public roads. As far as I know, this has always been the case. Maryland plates with the legends "Trac" or "Tractor" were issued to non-farm truck tractor trucks. Maryland plates with the legend "Farm Tractor" do exist, but these were issued to farm-use truck tractors, not to actual farm tractors as most people understand the term.

1954-1975 mobile equipment
No information available. Probably this plate category did not exist prior to the 1976-1980 base. Mobile equipment would likely have been issued either truck or trailer plates, depending on whether the equipment was self-propelled.

1976-1987 mobile equipment
These plates were issued to motor vehicles and trailers using public roads that really could be considered more tools than transportation, such as cranes, mobile compressors, wood chippers used by tree removal businesses, and the like. Serial format was 00000 and the plates bore the embossed legend "Spec Equip", which stood for "Special Equipment".

1987-present mobile equipment
Equipment plates on the screened "Maryland" base follow the format of dealer and automotive business plates. Only single plates are issued. They have serial format 4E00000 and the screened legend "Special Mobile Equipment" at the bottom. The need for the word "special" in the legend is unclear, since there is no regular, non-special mobile equipment category. My understanding is that these plates are not registered to specific vehicles; thus a business that had 20 pieces of mobile equipment, but only 5 drivers, might only need to obtain 5 license plates for their equipment.