Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 31
31
Since park-and-ride spaces encourage automobile access to Bridge. Since four freeways converge at the toll area at the east
stations and discourage pedestrian, bicycle, and bus access, bay approach to the bridge, the six lanes (for each direction)
this implies that the transit line is designed to primarily serve of the bridge serve as a bottleneck to the ten lanes that feed it.
corridor trips for people living within the corridor, as opposed Both employment and housing densities (9.3 and 3.5 per
to casting a wider net and attracting automobile-to-transit acre, respectively) are below the study averages (12 and 5 per
transfers that often originate farther away. acre, respectively). The density of four-legged intersections in
The placement of the Blue Line's stations in relation to the the corridor is similarly below average and together with the
highway facility encourages non-automobile access as well. other urban form indices, suggests a moderately automobile-
On average, the distance from the corridor's stations to the oriented corridor. However, there are meaningful variations in
highway is roughly 0.20 mile--higher than the average distance the corridor's urban form that help explain its success. Down-
for the rest of the study corridors of 0.15 mile. However, most stream of the Caldecott Tunnel, the corridor runs through the
of this high average distance is due to the separation of stations inner-ring suburbs and increasingly urban areas of Berkeley
from freeway in the downstream segment, where the gap is up and Oakland. This segment has higher residential densities
to a half-mile, while the upstream segment has stations placed than the upstream segment, where more recent, low-density
largely in the median of the freeway. This relatively large suburban development patterns have dominated.
distance in the downstream segment mitigates some of the Similarly, the corridor's stations are best described as
negative impacts of the highway on the transit line and has automobile-oriented in design and function, but the upstream
allowed the station areas there to maintain a transit-oriented stations more so than the downstream stations. Overall, the
urban form. Overall, these factors combine to make this cor- average number of park-and-ride spaces per station in this
ridor one of the most transit-friendly, in terms of urban form, corridor is roughly 1,600--more than double the study average
of the study cases, largely due to its transit orientation of the of 620. The corridor's stations are also very close to the high-
downstream segment. way (roughly 0.05 mile on average, compared to the study
average of roughly 0.13), providing an attractive option to
San Francisco East Bay (BART) Pittsburg/ highway drivers to exit, quickly park, and complete their
Bay Point Line/S.R. 24 trips via BART. However, the most automobile-oriented
stations are generally in the upstream segment, while the
The San Francisco BART's Pittsburg/Bay Point line runs
downstream segment's stations tend to have fewer park-
from the East Bay suburbs of Pittsburg, Bay Point, Concord,
and-ride spaces and are designed to be friendlier to pedes-
and Walnut Creek to downtown Oakland and San Francisco.
trian access.
Here, as in the cases discussed above, restricting the freeway's
In terms of multimodal coordination, the average station
capacity has been important to the adjacent transit line's
spacing for the Pittsburg/Bay Point Line (6.42 miles) is dramat-
success. But in the Pittsburg/Bay Point corridor, there are
ically longer than the average interchange spacing for State
actually two freeway capacity constraints. The first occurs
Route 24 (0.93 mile), resulting in a highly complementary
where Highway 24 and the BART line bore through the
corridor with a Coordination score of 5.5 miles. However,
Oakland/Berkeley hills to reach the core Bay Area; the Caldecott
Tunnel shrinks the freeway's capacity from eight to six station spacing gets shorter in the downstream segment,
lanes. The center bore of the tunnel is reversible, so during providing better access from the BART line to the local land
commuting hours, the peak direction of flow always has uses than in the upstream segment. Clearly, this configuration
four lanes of travel. However, the nonpeak direction is re- provides a speed advantage to the BART line in the upstream
duced to two lanes, and as a result, there is almost always segment compared to other heavy rail systems with shorter
congestion and delay in both directions of travel during the station spacings and, functionally, means the line in the
A.M. and P.M. peak commute hours at the tunnel. While this upstream segment operates almost more as a commuter rail
nonpeak-direction capacity constriction does not directly line than heavy rail. This higher operating speed, plus the
encourage peak direction use of the BART line, it does restrict near-constant congestion at the Caldecott Tunnel and the Bay
nonpeak direction flow, thereby providing direct incentive for Bridge, gives the BART line a chance to capture a respectable
nonpeak direction BART ridership and indirectly promoting share of corridor travel.
the general perception that BART is the more hassle-free
corridor alternative.
Corridor Evolution
The second constraint occurs at the San Francisco Bay
crossing itself, where BART runs in a submerged tube beneath Corridor travel patterns and built environments can change
the water and mud of the bay floor, while automobiles run in dramatically over time. Often, changes in land uses and trans-
a parallel alignment across the San Francisco-Oakland Bay portation facilities affect each other. The new paradigm offers
OCR for page 32
32
ideas and tools to harness, guide, and shape these changes, the evolution of freeway-only, automobile-oriented, and old
with the goal of creating a corridor where all modes can paradigm corridors into transit-oriented corridors. Park-
flourish within a sustainable and livable environment. and-ride-access and transit-optimized/freeway-constrained
Although the new paradigm typology offers three scenarios, corridors need not be seen as end-states, but steps along the
as described above, each of these should not be seen as a nec- evolutionary path toward livable, sustainable, efficient transit-
essary end-state. The new paradigm is designed to encourage oriented corridors (see Figure 3-2).
Freeway-Only Corridor
- Freeway dominates corridor travel
- Automobile-oriented land uses
Old Paradigm Multimodal Corridor LEGEND
Transit Line
- Freeway dominates corridor travel
- Transit as congestion reliever Transit Sta.
- Automobile-oriented land uses Freeway
- Long int. & sta. spacings
- Sta. & int. co-located Freeway Int.
- Park-&-ride access emphasis for sta.
New Paradigm Corridor: Park-&-Ride Access
- Transit focused on long-haul corridor trips
- Freeway focused on short-haul trips
- Automobile-oriented land uses
- Short int. & long sta. spacings
- Sta. & int. co-located
- Park-&-ride access emphasis for sta.
New Paradigm Corridor: Transit-Optimized/
Freeway Constrained
- Hybrid multimodal corridor
- Park-&-Ride segment: upstream
- Transit-Oriented segment: downstream
Upstream (Non-CBD) Segment Downstream (CBD) Segment
Freeway Capacity
Constraint
New Paradigm Corridor: Transit-Oriented
- Transit focus on local access & short-haul trips
- Transit-oriented land uses
- Long int. & short sta. spacings
- Sta. & int. separated except for intermodal sta.
- Non-automobile access emphasis for sta.
Figure 3-2. Possible paths to developing transit-oriented new
paradigm corridors.
OCR for page 33
33
Therefore, although the success of the new paradigm requires planners often must give up on the idea of competing with
the identification of a clear, consistent and widely supported the freeway on the basis of comparative travel times or offer
vision for what the multimodal corridor will look like and a higher level of accessibility to corridor land uses. In the
how it will function in the long term, it does not require these planned Greenwich/Norwalk BRT line, system planners are
changes to all take place at once. Rather, a long-term vision focusing on incremental improvements to existing corridor
can be realized through a series of incremental improvements transit services that provide improved transit travel times
over time, with each step building on the last to create gradual between the relatively dense urban centers of Greenwich and
and sustainable changes. Norwalk, Connecticut.
Introducing a new transit line to a corridor is particularly While a full BRT alternative was considered, corridor
challenging, for all the reasons discussed in this report. There- planners opted for a more incremental approach. Planned
fore, it is often unrealistic to assume that even the most radical improvements include an on-street signal preemption system
and well-financed changes to an existing automobile-oriented, to reduce intersection delays, a "priority lane," which will be
freeway-only corridor can yield a successful transit-oriented shared between transit vehicles and mixed traffic, queue-jump
new paradigm corridor immediately. However, if transit is lanes, and a suite of intelligent transportation systems to
introduced using the principles of the new paradigm's park- provide real-time bus arrival and departure information at
and-ride access model, it can establish its own share of the cor- bus stops, travel times, schedule adherence, and automatic
ridor's travel market. Once successful as a park-and-ride access announcement information.
corridor, incremental changes can be introduced that can help In addition, incremental improvements will be made to
it transition to becoming more transit-oriented over time. intermodal terminal stops to improve quality of service and
Bus rapid transit can be a cost-effective park-and-ride access reduce dwell times. Figure 3-3 illustrates the improvements
mode to start this evolutionary process. The following sections to routing that the "enhanced bus service" will provide and
describe how BRT and other incremental improvements can also shows the alignment of a dedicated transitway that will
be introduced as stepping stones leading to a more transit- give dedicated right-of-way access into the Stamford Trans-
oriented new paradigm corridor. portation Center.
Incremental Transit Improvements: Hybrid Multimodal Corridors:
Steps Toward Full BRT and the New Paradigm Taking Advantage of Changing
Corridor Urban Form
Off-freeway BRT alignments in multimodal corridors can
be problematic. When BRT does not run on a grade-separated No two corridors are the same. Each metropolitan area,
alignment and must travel in mixed-flow, on-street traffic, and each corridor, has different travel patterns and built envi-
Source: Courtesy of South Western Regional Planning Agency and AECOM, Greenwich/Norwalk Bus Rapid Transit Study.
Figure 3-3. Planned incremental improvements to the Greenwich/Norwalk Bus
Rapid Transit Line over time include the construction of a bus-exclusive transitway.
