Civil Engineering Reference
In-Depth Information
(a) Lines should penetrate, rather than skirt, major market areas such as high-
density residential neighborhoods, schools, medical centers, and outlying
business areas. This practice makes it possible to increase ridership beyond the
CBD market.
(b) A simpli
ed route structure is essential. Therefore the number of branches
should be minimized. Ideally heavy rail transit lines should have only one
service per track, and never more than two.
(c) To maximize operating speeds, it is desirable to space stations far apart. Sta-
tion spacing should re
ect development densities and access modes. For walk
access typical station spacing is 0.5 miles; for bus access is 0.5
fl
1.0 miles; and
-
3 miles.
(d) Convenient access to stations is essential. Good pedestrian access is important
for all stations, especially those located in high density areas. Convenient bus-
rapid transit interchange is necessary where bus lines serve or converge at
stations. Escalators and elevators should provide necessary vertical transpor-
tation. Adequate park-and-ride facilities are essential at suburban stations since
an inadequate supply of parking space can limit transit ridership.
(e) Transit-supportive development should be encouraged around stations that are
currently surrounded by medium-to-high residential and commercial activities.
This could enhance the station environs, increase transit ridership, and reduce
automobile trips.
when access is by car it is 1.5
-
23.5.4 Congestion Implications of Rapid Transit Lines
Various rapid transit systems built before the automobile era, have had several
congestion-related effects over time. They have made it possible for city centers to
grow in density and they have induced residential development along their lines.
Although the lines were grade-separated in the city centers, they induced
employment growth resulting in major concentrations of activities that, in turn,
increased the severity of street congestion
—
at least until traf
c engineering was
effectively applied in the downtown areas.
The congestion effects of major transit investments are somewhat different
today. Urban dispersion has been more a phenomenon of the automobile. Longer
travel distances have resulted in increased peak period freeway congestion. In
contrast, grade separated transit provides improved mobility and can attract auto-
mobile travelers. Extensive park-and-ride facilities at outlying locations can reduce
car trips destined to the CBD and street congestion. Even more signi
cant, perhaps,
is the ability of rapid transit lines to support concentrated developments around
stations thereby reducing dependence on the automobile for travel mobility.
