State

These plates are used on state-owned vehicles – Capitol Police cars to tractors.

This type started sometime in the mid 1940s.

The numbered prefix on these plates is a code for the department/agency to which the plate is issued.

Click Here for a partial listing of these codes, and feel free to contribute any additions.

Click the photo to see this type in use.

I estimate this plate to be from the very early 1950s.
Another format was later introduced on 6×9 plates with stacked prefix numbers. This plate is 6-1/2″ x 11″.

1960s / Early 1970s
University of Connecticut

1960s / Early 1970s
This plate was from the now-closed Norwich State Hospital, which opened in October 1904 as the “Norwich Hospital for the Insane”.

Late 1970s – Early 1980s
Department of Transportation

Late 1970s – Early 1980s

Map base – late 1980s through 1990s

Same, probably from a highway maintenance vehicle

4-digit State plate. These had up to 5 digits in the general motorpool (5- prefix), for example 5-12345

‘State’ plates were one of the last types to be completely replaced in the general reissue. Plates of this style were still use on some state vehicles such as buses, tractors, etc. for about 4-5 years after the general reissue.

State Service Bus

These plates are used on state-owned buses which do not charge a fee for transportation.

These plates are typically used on buses belonging to the State Vocational schools, the State University system, and prisoner transport buses.

This type started sometime in the 1970s.

Beginning in 2016, as with pretty much all of the other formerly all-numeric types these plates now use the AB-12345 numbering format.

Click the photo to see this type in use.

Circa 1970s, revalidated to 1989