Rick Kretschmer's License Plate Archives 

There were two types of bus plates issued by Pennsylvania during the mid- and late-1920s.  One type used a letter "O" serial prefix, and the other used an "H" prefix.  The full-sized "O" on 1924-26 plates looks like a lead zero, but it's not.  It's been the reported that the "O" plates were issued to buses, and the "H" plates were issued to omnibuses.  I've seen no hard evidence to support this, however, and I have my doubts.  I suspect that it could have been just the opposite, or perhaps "O" plates were used on buses while "H" plates were used on taxis.  The letter "H" was used on taxi plates by several other jurisdictions at the time, including Maryland, the District of Columbia, and Virginia. 

What, exactly, is an omnibus, and how does it differ from a regular bus?  I wish I knew.  A 1980s document from the Pennsylvania Department of Motor Vehicles indicates that bus plates are issued to commercial buses that charged fares, while omnibus plates were issued to private buses and other buses for which no fare is charged.  Whether these definitions were the same in the 1980s as they were in the 1920s, I can't say. 

It would seem that the "H" prefixed bus or taxi plate type was discontinued after 1929.  1930-1933 plates with the letter "H" in the plate number are vastly more numerous than 1920s "H" plates, and so I'm reasonably certain that early 1930s "H" plates are just passenger car plates.  It's hard to be completely certain, because Pennsylvania plates from this era did not use a legend to identify the plate type. 

The surviving plate type for buses and taxis was that with the letter "O" prefix.  Whether "H" and "O" plate types were merged into the "O" plate type, or something else happened, I just don't know.  By 1930, if not sooner, the dash used between the prefix letter and the numeric digits was eliminated. 

For 1934, and continuing to the present, bus plates bore a Bus legend that clearly identified them as such.  Serial formats in 1934 did not use the "O" letter code; instead, they were all-numeric.  However, the "O" returned, always as a prefix letter, starting in 1935.  Bus plate numbers did not exceed four numeric digits during these years.  Although 1937 passenger car plates were issued with a state map outline, bus plates continued in the plain style for one additional year. 

It's my understanding that "Bus" plates were issued to not just buses, but also to taxis and possibly other types of commercial passenger vehicles. 

Regular buses

Starting in 1938, bus plates bore the state map outline that was introduced on passenger car plates in 1937.  Again, the first serial character was always a letter "O".  Initially, the characters following the "O" were only numeric digits, but by 1946, if not sooner, plate number O9999 was issued, exhausting the format.  Additional bus plates were then made each year through 1955, or possibly 1956, with serial format Ox000, where the second character is a variable letter.  This second format might not have been needed in 1956, with the introduction of the school bus plate type.  In any case, the legend at the top of regular bus plates was yy# Bus #Pa, with # indicating the positions of embossed keystones. 

Like other plate types, the registration period was changed from the calendar year to end on March 31 of the year following the year indicated on the plate, beginning with the 1941 plate.  Starting with this plate, the actual expiration date was added in very small characters along the top edge of the plate.  The expiration date of bus plates was changed again effective with the 1953 plates, to be May 31 of the year following the year indicated on the plate.  Passenger cars continued with March 31 expiraiton dates. 

1957 regular bus plates abandoned the previous serial formats, and instead used a six-character O00000 format, which, if you can't tell, is the letter "O" followed by a five-digit number.  I believe the plate numbers began at O10000. 

School buses, 1956-1957

The school bus plate type was introduced in 1956.  I assume that prior to 1956, school buses were issued regular bus plates.  In any case, 1956 and 1957 school bus plates bore the legend Pa. School Bus across the top of the plate.  The four-digit registration year was embosssed on the left side of the main part of the plate, running diagonally.  The expiration date embossed on the top edge of the plate was June 30 of the year following the registration year.  In other words, 1956 school bus plates indicated a 6-30-57 expiration date.  As far as I know, serial numbers were always four-digit numbers during these two years. 

Regular buses

Continuing the serial format introduced in 1957, regular bus plates had a six-character serial number consisting of the letter "O" followed by a five-digit number, apparently starting at 10-000.  A small keystone separator was introduced, located between the third and fourth serial characters.  Stamped along the top of these plates were Pa Bus 58 and Pa Bus 64, respectively.  The expiration date for regular bus plates continued to be May 31 of the year following the year indicated on the plate or sticker. 

School buses

School bus plates were initially assigned four-digit serial numbers, starting at 1000, with no keystone separator between any of the digits.  After plate number 9999 was issued, serial numbers then continued with five-digit numbers.  Stamped along the top of these plates were Pa School Bus 58 and Pa School Bus 64, respectively.  At least through the 1966 registration year, the expiration date continued to be June 30 of the following year.  Sometime between the 1967 and 1971 registration years, the expiration date for school bus plates was changed from June 30 of the year following the plate or sticker year to July 31. 

Regular buses

Regular bus plates were issued to both non-school buses and taxis.  They bore the legend Bus along the top edge of the plate.  The "O" prefix was dropped in favor of a "BA" prefix, and the serial format became BA-00000.  The small keystone separator continued to be used, but was moved between the serial letters and numbers.  The expiration date for regular bus plates continued to be May 31 of the year following the year indicated on the plate or sticker. 

School buses

School bus plates bore the legend School Bus along the top edge of the plate.  The serial format acquired a two-letter prefix, now SA-00000.  A small keystone separator was placed between the serial letters and numbers.  Sometime between the 1967 and 1971 registration years, the expiration date for school bus plates was changed from June 30 of the year following the plate or sticker year to July 31. 

Regular buses

1972 to 1977 regular bus plates were yellow on blue, again with the legend Bus at the top.  The state name was at the bottom, with sticker wells in both upper corners.  The state map outline, which had become grotesquely distorted in 1968, was put out of its misery.  Serial format BA-00000 was again used, with a small keystone serial separator.  Early issues had a lightly etched "72" in the left sticker well.  The plate was used without stickers during the 1972 registration year; stickers were applied to validate the plate during the 1973-1977 registration years.  Like trucks, and opposite from passenger cars, bus plates used blue-on-white stickers for odd years and red-on-white stickers for even years. 

School buses

School bus plates again bore the legend School Bus along the top edge of the plate, and the serial format was again SA-00000, with a small keystone separator between the serial letters and numbers.  However, these plates were made in the opposite colors from most other plate types during these years.  School bus plates on the 1972 base were made with blue characters on a reflective yellow background.  Most plate types didn't get this color scheme until at least 1977, and plate collectors have tended to incorrectly assume that improper stickers were applied to applied to a 1977 or 1978 base plate.  However, this is clearly not the case; early versions of school bus plates on this base, including the one shown at left, have a debossed "72" in the left sticker well.  Numbering began at SA-10000.  I'm not sure whether 1972-1977 school bus plates were replaced in 1978, some time later, or not until the 1999-2000 replacement of all yellow plates. 

Omnibuses

The omnibus plate type was introduced (or re-introduced) some time betwee 1972 and 1975, but I'm not sure exactly when.  A 1980s document from the Pennsylvania Department of Motor Vehicles indicates that regular bus plates are issued to buses that charged fares, while omnibus plates are issued to private buses and commercial buses on which no fare is charged.  The serial format on omnibus plates was OB-00000, with a dash or hyphen separator, rather than the usual keystone separator, between the serial letters and numbers. 

Like school bus plates, omnibus plates on the 1972 base were made in the opposite colors from most other plate types during this time, with blue characters on a reflective yellow background.  However, unlike other plate types from this period, Omnibus plates bore the state name at the top, the legend indicating the plate type at the bottom of the plate.  This is the same color scheme and format that other non-passenger plate types didn't get until the 1977 or 1978 base, depending on the type.  As a result, plate collectors have sometimes incorrectly assumed that improper stickers were applied to applied to a 1978 omnibus base plate. 

Again, I don't know whether these were replaced in 1978 or continued to be renewed with stickers in 1978 and beyond, with expirations as late as 2000. 

Regular buses

Blue-on-reflective yellow regular bus plates were introduced in 1978 as a general replacement for the previous base.  On these, the legend Bus was moved to the bottom of the plate, while the state name was relocated to the top.  Sticker wells continued to be located in both upper corners.  Serial format BA-00000 was again used, but now with a dash separator.  These plates were undated and were used without stickers during the 1978 registration year; stickers were applied to validate the plate beginning in the 1979 registration year.  Beginning on this base, bus plate stickers were made using the same colors as stickers for all other plate types.  With the introduction of the omnibus plate type several years prior, and now the taxi plate type, regular bus plates on this base were used only for commercial buses that charged fares, including charter buses, and I believe also for limousines for hire. 

Apportioned buses

Apportioned plates are issued to certain commercial vehicles that cross state lines.  Apportioned bus plates are required only on fixed-route, long-distance buses that cross state lines.  Charter buses and urban transit buses that cross state lines are explicitly exempt from apportionment requirements.  Since most buses registered in Pennsylvania are either charter buses or transit buses, apportioned bus plates were and still are infrequently seen. 

Apportioned bus plates had an Apportioned legend at the bottom, and serial format BL-00000.  Apportioned plates in format Ax-00000 were issued to trucks and truck tractors.  All apportioned plates expire annually each May 31.  Information available online indicates that Pennsylvania entered the International Registration Plan (IRP) on June 1, 1983, so logically, the earliest stickers on apportioned plates should indicate a May 1984 expiration.  However, I've seen Pennsylvania apportioned plates bearing May 1983 stickers, which would contradict this.  I suspect that the correct date of entry into the IRP may actually be June 1, 1982. 

Mass transit buses

The mass transit plate type was also introduced on the 1978 blue-on-reflective-yellow base, but I don't know exactly when.  I would guess that this type was issued no later than the debut of the apportioned plate type in the early 1980s.  I presume that transit buses had been issued regular bus plates prior to the introduction of the mass transit plate type.  Mass transit plates bore the legend Mass Transit along the bottom edge of the plate, and used a serial format M/T 00000, where the letters "M" and "T" were small and stacked one above the other.  Why they chose to stack the prefix letters and omit the dash separator is beyond me. 

School buses

School bus plates continued unchanged from the yellow 1972 base, with the legend School Bus along the top edge of the plate, and a small keystone separator between the serial letters and numbers; both of these features are different than just about all other plate types on the reflective yellow base.  I think that possibly 1972-1977 school bus plates were not replaced, but continued to be used in 1978 and beyond, as late as 2000.  However, somewhere along the way, when plate numbers were up into the early SA-40000 series, for no apparent reason the numbering skipped to SB-10000 for newly-issued plates.  It may be that 1972-1979 plates with the "SA" prefix were replaced in 1980 or later with "SB"-prefixed plates.  I need to see more of these yellow school bus plates to be able to figure this out.  Numbering of the yellow SB plates got up to about SB-24999 or so. 

I was under the impression that all school bus plates have July expirations.  I don't have an explanation for the school bus plates I've occasionally seen with expiration months other than July, such as the one at left with a June expiration month. 

Omnibuses

The omnibus plate type on the 1972 base looked just like other plate types on the 1978 base, and so no design changes were made.  These plates continued with the state name at the top, the legend indicating the plate type at the bottom, and serial format OB-00000, with a dash or hyphen separator between the serial letters and numbers.  It's possible, but not certain, that pre-1978 omnibus plates were not replaced, but continued to be used in 1978 and beyond, as late as 2000. 

Again, a 1980s document from the Pennsylvania Department of Motor Vehicles indicates that omnibus plates are used on private buses and on commercial buses on which no fare is charged. 

Taxis

After decades of having to endure the indignity of displaying bus plates, taxis finally were finally granted their own plate type early in the life of the yellow base.  It's been reported elsewhere that taxi plates made their debut in 1977, but I suspect that it was actually in 1978.  The undated yellow base was introduced in 1977 for passenger cars, but not until 1978 for nearly all other vehicle types.  If taxi plates were like these other types, these plates were used without stickers during the 1978 registration year, and stickers were applied to validate the plate beginning in the 1979 registration year. 

In any event, the serial format was TX-00000, with the letters "TX" constant, and the legend Taxi was embossed at the bottom of the plate.  Numbering got up into the TX-24000 series on this base. 

Regular buses

The serial format continued to be BA-00000, and picked up where the previous base left off, somewhere between about BA-34000 and BA-36000.  The state name was moved to the bottom and the Bus legend to the top, making these plates strikingly similar in appearance to the 1972-1977 bus plates.  There are several ways to distinguish them, however, even if the plate does not have an expiration sticker.  The 1970s bus plates had two sticker wells in the upper corners, while these bus plates had a single sticker well in the lower left corner.  The earlier plates had a keystone separator, while the later plates had a dash separator.  And, I haven't come across a blue 1970s bus plate past the early BA-30000 series, while the blue 1980s bus plates began in the mid BA-30000 series. 

By now regular bus plates were used mostly on charter buses, and if there were any, on fixed-route, long-distance, in-state buses.  These blue regular bus plates were (supposed to be) replaced with fade-band tri-color plates bearing the same plate number between July 2000 and June 2002. 

Apportioned buses

It's been reported that apportioned bus plates were issued on the blue base, but I've never even seen a photo of one, so I'm not prepared to accept this as fact.  If any exist, they were replaced with fade band plates upon expiration in May 2000.  I wouldn't be surprised to learn that yellow-background apportioned bus plates were issued all the way to the introduction of tri-color fade plates in September 1999. 

Mass transit buses

The serial format continued to be M/T 00000, with the letters "M" and "T" stacked one above the other, and the plate numbers picked up where the previous base left off, at about M/T 18000.  The legend Mass Transit legend was moved to the top of the plate, and the state name to the bottom.  This plate type was also replaced between July 2000 and June 2002, but new plate numbers were issued on the tri-color fade base. 

School buses

The serial format continued to be SB-00000; the numbers on the blue base seem to have started at about SB-25000 and go up at least into the early SB-60000 series.  The school bus plate type remained an oddball, however, because they continued to use a keystone separator rather than a dash.  The plate type legend School Bus remained at the top of the plate and the state name at the bottom, now consistent with most other plate types on this base.  I was under the impression that all school bus plates have July expirations; I don't have an explanation for the school bus plates I've occasionally seen with expiration months other than July.  I've seen them with dates as late as July 2002 on the blue base, so this type might be an exception to the July 2000 through June 2002 general replate.  New plate numbers were issued on the tri-color fade base. 

School vehicles

This new plate type was introduced on the blue base, possibly in the late 1980s or early 1990s.  I presume that a "school vehicle" is a van or mini-bus painted yellow and configured and marked as a school bus.  Probably before this plate type was introduced, such vehicles were issued school bus plates.  Why there needs to be a distinction between the two escapes me. 

In any event, these plates have the plate type legend School Vehicle at the top and the state name at the bottom, consistent with other plate types.  Serial format is SV00000, inexplicably without a separator between the letters and numbers.  All school vehicle plates were replaced with fade-band plates between September 1999 and January 2000, regardless of the expiration date indicated on the old plate.  New plate numbers were used on the replacement plates. 

Omnibuses

The serial format continued to be OB-00000, but there seems to be a gap between the highest-seen yellow plate number in the OB-23000 series and the lowest-seen blue plate number in the OB-27000 series.  Like on most other plate types, the state name was moved to the bottom and the plate type legend was moved to the top.  All omnibus plates were replaced with fade-band plates between September 1999 and January 2000, regardless of the expiration date indicated on the old plate.  New plate numbers were used on the replacement plates. 

Taxis

The serial format continued to be TX-00000, with the blue plate numbers starting at approximately TX-25000.  The state name was moved to the bottom and the Taxi legend to the top.  According to PennDOT, all taxi plates were replaced between September 1999 and January 2000, regardless of the expiration date indicated on the old plate.  New plate numbers were used on the fade base replacement plates. 

Limousines

This new plate type was introduced on the blue base, I believe some time in the early 1990s.  I'm not sure whether this plate type is issued to all limousines, or only limousines for hire.  I suspect the latter.  In any case, I'm under the impression that, similar to taxis, vehicles that now get limousine plates were issued regular bus plates prior to the introduction of this plate type.  Serial format was LM-00000, with a dash separator, and the word Limousine was embossed at the top of the plate.  Limousine plates were replaced with fade-band plates between September 1999 and January 2000, regardless of the expiration date indicated on the old plate.  New plate numbers were used on the replacement plates. 

Regular buses

Unlike most other plate types, yellow-background and blue-background bus plates were replaced with fade-band base plates bearing the same plate number.  Why this was done is unknown.  These replacement bus plates had no space or separator character between the plate letters and numbers, and so were in format BA00000.  Plate numbers up to at least BA47999 were in this format. 

Newly-issued regular bus plates on the fade base do have a dash separator, in format BA-00000, and plate numbers ranged between no later than BA-48200 and BA-59999.  Solid-band plate numbers began at BA-60000. 

If you're paying attention, you noticed that the fade band bus plate at left has no serial separator but is outside of the number range of plates that should have no serial separator.  Indeed, John McDevitt shows photos of plate numbers BA-48006 and BA-48277 both with embossed dash separators.  No one knows why BA-48006 has a separator but BA48106 does not.  One or the other of these might be error plates. 

Apportioned buses

Apportioned plates are issued to certain commercial vehicles that cross state lines.  Apportioned bus plates are required only on fixed-route, long-distance buses that cross state lines.  Charter buses and urban transit buses that cross state lines are explicitly exempt from apportionment requirements.  Since most buses registered in Pennsylvania are either charter buses or transit buses, relatively few apportioned bus plates are issued, and they're infrequently seen. 

Apportioned bus plates use the format BN-00000.  Plate number BN-02343, shown at left, was the highest apportioned bus plate number observed thus far (and therefore recently issued) when I photographed it in October 2012.  As you can see, this type is still being issued on the fade base.  All apportioned plates have May expirations, and have a distinct expiration sticker that says Pa Apportioned across the top, rather than Pennsylvania. 

Mass transit buses

Mass transit bus plate numbers on the fade band base began at M/T 30000, again with the prefix letters stacked and with no space or separator between the stacked letters and the numbers.  Starting at MT-33000, mass transit plates took on a more conventional appearance, with full-sized prefix letters and a dash separator between the letters and numbers.  However, when the solid band base began at M/T 40000, the format reverted back to the stacked prefix letters and no separator or space. 

School buses

School bus plates advanced to the next letter prefix, starting at plate number SC-00000 and going up to SC-46999 on the fade base.  Unlike virtually all other plate types, school bus plates continued to use a small keystone separator on the fade base.  Solid band plates went to the larger keystone separator used on other plate types, with plate numbers beginning at SC-47000. 

School vehicles

School vehicle plates had plate numbers ranging from SV14000 to SV17499 on the fade band base, again always without any kind of space or separator between the letters and numbers.  Solid band plates began at SV17500.  On the solid band base, school vehicle plates have gone back and forth several times between having no space or spearator, and having a conventional keystone separator between the letters and numbers as is done on other plate types. 

Omnibuses

Omnibus plate numbers on the fade band base began at OB-50000 and went up to OB-68999.  They began at OB-69000 on the solid band base.  Fade plates employ a dash separator, while the solid band plates use a keystone separator.  Omnibus plates are issued to private buses and commercial buses that don't charge fares. 

Taxis

Taxi plate numbers on the fade band base began at TX-35000 and went up to TX-45999.  They began at TX-46000 on the solid band base.  Fade plates employ a dash separator, while the solid band plates use a keystone separator. 

Limousines

Limousine plate numbers on the fade band base began at LM-20000 and went up to LM-26999.  They began at LM-27000 on the solid band base.  Fade plates employ a dash separator, while the solid band plates use a keystone separator.