These plates are issued to amateur (ham) radio operators.
This type reportedly was first available on March 1, 1956. These plates were black on reflective white scotchlite.
The operator’s callsign is the registration number, with the neat lightning bolt separator. The lightning bolt seems to get smaller and smaller with every iteration.
Around 1981, these plates were also made available for use on Combination registrations. Commercial and Camper are available today as well.
Click the photo to see this type in use.
1957
ca. 1957 used until 1973
ca. 1957 – tab slots and the back of the plate is blue.
ca. 1968 – no tab slots and a white back.
It also appears that the second ‘W’ is an inverted ‘M’.
1974
ca. 1974/1975 revalidated until 1988
1979
1988
Map Base (1990s)
Map Base (1990s)
Sample/Test plate on the “Preserve the Sound” base