The predecessor to BB57, the B615 had gone out of production in 1965, but apparently the demand for such a model was so high that they had to bring it back almost half a decade later, as the B54 proved to be too small.

This chassis type was rare in the United Kingdom, but was quite popular in rural parts of the Nordic countries.

Singapore Bus Service introduced a fleet of 350 New Zealand Motor Bodies bodied B57s between 1980 and 1983 following a successful trial of a Metal Sections-bodied demonstrator in 1979.

Of these, the first 200 units were fitted with Version 1 of the bodywork, which hard a raised angular roof for the front destination signage, and the balance 150 units fitted with Version 2 of the bodywork, which had a curved roof for the front destination signage.

In Pakistan, the Punjab Urban Transport Corporation placed 300 in service in Lahore.