  In-medium properties derived for nuclear matter in a microscopic pi +
nucleon-hole + delta-hole model are incorporated into transport simulations of
nuclear collisions by means of a local-density approximation and by utilizing a
local medium frame. Certain features of the transport results differ from those
based on the corresponding vacuum properties. Comparisons of the pi and delta
production rates, as well as pion energy spectra, are discussed in particular.
