H House Trailer. This is a new prefix beginning 1961. [Emphasis ours.]
This information, coupled with the absence of H plates for 1956-1960, establishes with a high degree of certainty that the H prefix was dropped after just one year of use in 1955, then reinstated in 1961.
It was stated by the DMV in 1964 that H plates were being “issued to all camper or dwelling type house trailers,” and that registration fees were based on the number of axles. [See press release, “Vehicles Subject to New Mexico Registration,” Benny E. Sanchez, Motor Vehicle Commissioner, July 31, 1964] The last use of the H prefix was a 1971 base revalidated with a 1974 sticker. This type was then replaced by the MH plate, the new prefix standing for “Mobile Home.” The MH plate actually first appeared in 1973, so there was a two-year overlap during which some existing H-prefix plates could be renewed, such that both H and MH plates were in use concurrently. Whereas House Trailer (H) plates were renewed annually, the subsequent Mobile Home and Manufactured Home (MH) tags were permanent plates. Please see the sections on Mobile Home and Manufactured Home plates for more details on those types.
