Results with Respect to Density
Map 2 displays the net residential density in 1990 for 1990 block groups, while Map 3
displays the percent change in net residential density from 1980 to 1990 by 1990 block
groups. Gross residential density divides the number of dwelling units by the gross
acreage of the block group, while net residential density divides the number of dwelling
units by the area devoted to residential use in 1980 and in 1990 as determined by the yearbuilt
variable in Portland Metro’s Regional Land Information System (RLIS).
Figure 3 presents the density values for the two corridors and their inner and outer portions
that reflect the central city and suburban portions, and Figure 4 presents percent change
from 1980 to 1990. (Figures 2 and 3 are based on data in Table 6.) This aggregation of
density from the block group level to the corridor level facilitates comparison of the
corridors. Interestingly, it shows that the density increase in the rail corridor is less than in
the bus corridor, which may be another indication that LRT alone is not sufficient to
increase residential density. The losses in residential density for both rail and for net
density, bus, may be due to increasing commercial uses in the inner portion of the study
area.