  We have observed the galaxy environments around a sample of 21 radio-loud,
steep-spectrum quasars at 0.5<z<0.82, spanning several orders of magnitude in
radio luminosity. The observations also include background control fields used
to obtain the excess number of galaxies in each quasar field. The galaxy excess
was quantified using the spatial galaxy-quasar correlation amplitude, B_gq, and
an Abell-type measurement, N_0.5 (Hill & Lilly 1991). A few quasars are found
in relatively rich clusters, but on average, they seem to prefer galaxy groups
or clusters of approximately Abell class 0. We have combined our sample with
literature samples extending down to z=0.2 and covering the same range in radio
luminosity. By using Spearman statistic to disentangle redshift and luminosity
dependences, we detect a weak, but significant, positive correlation between
the richness of the quasar environment and the quasar's radio luminosity.
However, we do not find any epoch dependence in B_gq, as has previously been
reported for radio quasars and galaxies. We discuss the radio
luminosity-cluster richness link and possible explanations for the weak
correlation that is seen.
