Beginning the Dialogue - Report on SGR - Federal Transit ...

Core Capacity
r OVERVIEW
Rising public transportation ridership coupled with
expanding transit networks across <strong>the</strong> country are
putting pressure on <strong>the</strong> core capacity of many mass
transit systems. As new fixed guideway transit
systems are constructed and existing systems
leng<strong>the</strong>ned, many U.S. transit agencies are reaching
<strong>the</strong> upper limits of <strong>the</strong>ir infrastructure to
accommodate more passengers at chokepoints and
core areas.
The core capacity of a transit system represents <strong>the</strong>
maximum number of passengers or trips that can be
accommodated without having to widen or build
additional guideway or route infrastructure. Since
most transit systems tend to have concentrated areas
of destinations (such as central business districts or
transfer points), <strong>the</strong> core capacity of <strong>the</strong> system may
be constrained at a level below <strong>the</strong> maximum
capacity of individual components or segments (such
as outlying branches). Similarly, since transit trips
are not evenly distributed throughout <strong>the</strong> day, <strong>the</strong>
core capacity will be reached during periods of peak
usage. Because of <strong>the</strong> difficulty of funding <strong>the</strong> very
high cost of new guideway or route infrastructure,
and <strong>the</strong> time required to implement such expansion, it
is necessary to first explore all options for maximizing
<strong>the</strong> core capacity of <strong>the</strong> system.
r DETERMINING CORE CAPACITY
The following presents <strong>the</strong> issues and elements that
should be considered to maximize <strong>the</strong> core capacity
of a transit system without widening or building new
guideway. For convenience <strong>the</strong>se elements can be
grouped under <strong>the</strong> following categories:
n Network Strategies
n Line Capacity
n Vehicle Capacity
Core Capacity of a Transit System
FTA State of Good Repair Workshop
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n Station Capacity
n Support Capacity
n O<strong>the</strong>r Strategies
It should be noted that <strong>the</strong>se categories, and <strong>the</strong>
individual elements included in each, are not
necessarily independent variables but may be closely
related and have complementary or counteracting
impacts on capacity.
r NETWORK STRATEGIES
On systems with multiple routes and feeder services,
network strategies consider changes in <strong>the</strong>
configuration or operation of <strong>the</strong> system to make use
of available capacity. These strategies are discussed
here.
n Feeder Bus Modifications: Restructuring of
feeder bus routes to direct flows to alternative
lines or stations which have additional capacity to
absorb demand.
n Service Improvements on Alternate Lines:
Where ano<strong>the</strong>r line has excess capacity and <strong>the</strong>
potential to serve as an alternative route for
persons who are using a line experiencing
congestion and approaching core capacity,
increased frequency or o<strong>the</strong>r service
improvements on <strong>the</strong> alternative route could
induce some riders to switch to <strong>the</strong> less
congested line.
n Line Connections: On multiple-line systems
that intersect, consider building guideway
connections to reroute some services over less
congested parts of <strong>the</strong> system and to provide
greater flexibility in working around disruptions.
n Vehicle Consolidation: On multiple-line
systems that converge on a trunk, consider
merging and coupling single vehicles such as
light rail cars into trains, or leng<strong>the</strong>ning trains to