These plates are used on heavier commercial trailers. Private trailers typically use Camp Trailer plates.
I am not sure when this type started. The 1938 plate pictured below is perhaps the earliest known. Others have reported examples as early as 1932. Generally the size and colors have been the same as Commercial plates.
A peculiar practice which took place in Connecticut’s past was that heavy construction trailers (Oversize Load type) displayed TWO different trailer license plates on the back. Click the photo on the left to see an example of this. Sometimes they’re two consecutive plates, other times they’ve been issued a long time apart from each other.
Trailer plates reached the W-10000 series in mid-2011. In 2016 the universal format (AB-12345) made its way onto Trailer plates.
1938
1950, with yellow Scotchlite on stainless steel.
Prior to this, trailer plates were black on silver – the same as Commercial plates.
1951.
This style of plate was revalidated with corner date tabs through 1955.
1956. Silver on Black plates were used for Commercial and Trailer plates in ’56 and ’57. Late in this time period there was also a variant for Commercial plates with white letters – it would make sense that the same style would exist for Trailer plates.
1957
1958-59
This was once a license plate, and was once used at the New Britain Coal Yard.
1958. A more complete example. Actually, a very nice one.
1959
1960
Another 1960. The numbers were widely spaced until around plate 20000
1963
1964
1966
Numbers are now closer together.
1967
1967 Temporary Trailer
The license was temporary, not the trailer.
1966/1967 issue used until 1974
1974
1975
1982
1983
1986
Revalidated to 1991
From the beginning of this type, it appears to have taken over 40 years to exhaust its first numbering format, reaching 99999 in the mid-1980s.
1988
Once 99999 was reached, it was time for a new format. The obvious choice was an S-1234 format. Why? Who knows. Maybe for ‘Semi Trailer’?
1989.
When the map base came around in 1987, the next series was V-1234. Presumably this was done since it was the next series available after “S” (T is for Temporary, U is for Hearse).
1990
1991
1996
1997
1998
2000
2001
Although the decal is a 2001 expiration, it’s the same color as the 1999s. Perhaps a long-term registration?
2004
The map base was supposed to be off the roads in 2002; but a number of plates, especially trailers, ended up with the new decals on the old plates for a while.
mid-2000s
2011