| Contextual Infrastructure Planning and Design |
| On-Street Priority Transitways: Improving Urban
Mobility Using Available Rights-of-Way |
| By Mark C. Walker, New York, New York 1-212-465-5410, walkerm@pbworld.com
|
| Around the world, cities
faced with the challenge of improving transit service in urban areas
are considering exclusive transitways for buses, minibuses, or light
rail transit within existing street rights-of-way. In this article,
the author focuses on issues related to the planning and design of
on-street priority transit facilities. |
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Citizens may envision on-street transit facilities and planners
sometimes develop conceptual plans for them without completely understanding
their physical requirements or the available design options.
It is tempting to think that a street of fixed width can accommodate
a transitway, stations, travel lanes, parking, and landscaping without
compromises. In reality, trade-offs must be made among these competing
demands for street space. In fact, perhaps the greatest political
challenge to implementing such facilities is the fact that a transitway
introduced on an existing street will take space away from motorists.
Existing travel lanes and on-street parking may need to be reduced
and, in many cases, particularly outside of central cities, parallel
streets are not available to provide an alternate route and absorb
diverted traffic. The planning and design of on-street priority transit
facilities must try to minimize these impacts as well as coordinate
urban transportation, land use, and urban design.
Figure 1: Transit in the center (left), on one side (center)
and on both sides (right), 2 dimensional and aerial perspectives
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Basic Requirements of On-Street Priority
Transit Facilities
In an urban setting, on-street priority transit facilities can have
different configurations, but they must have certain characteristics
if they are to provide advantages over private cars or buses and streetcars
operating in mixed traffic. Whether for bus, light rail, or jitney,
on-street priority facilities must:
- Operate on the surface in an urban setting
with crossing pedestrian and vehicular traffic.
- Be primarily at-grade.
- Provide a semi-exclusive right-of-way where transit vehicles
operate free of competing parallel traffic.
The relationship between a transitway and surrounding land uses-both
transit-supportive land uses and those that conflict with a pedestrian-oriented
environment-is also critical to achieving the potential of priority
transitways. Particular emphasis should be placed on areas immediately
surrounding the stations, where access to land uses and pedestrian
volumes are greatest. Reserving these areas for retail commercial
uses, higher density employment and housing, and entertainment will
be mutually supportive of transit use. At the same time, excluding
automobile-oriented services and large parking lots from areas around
the transitway will increase the pedestrian orientation of those areas
best served by transit.
Urban design issues are also related to land use concerns, particularly
as they affect the pedestrian-orientation of public spaces and the
walking routes to and from the station. Located in the midst of the
street setting, on-street transit facilities offer particular opportunities
to:
- Coordinate the design of the facility and
stations with their immediate context
- Encourage development that contributes to the pedestrian character
necessary for a transit system.
For example, monuments, special lighting, or distinctive design elements
can create visual nodes that identify the location of transit stations.
Impacts on retail activity must be considered also, particularly with
relationship to parking, visibility and access. Fronting properties
and buildings may require vehicular or pedestrian access from the
road. Such a requirement may place a constraint on transit engineering,
but it can also create an opportunity for transit supportive land
uses. To the extent that these frontages are automobile-oriented,
with driveways and parking lots, or pedestrian oriented, with storefronts
along the sidewalk, they can contribute to or detract from the transit
environment.
Figure 2: Double-deck streetcars on paved median in Hong Kong |
Figure 3: Landscaped median in São Paulo |
Figure 4: Tubo Station in Curitiba, Brazil |
Figure 5: High-density land use along busway in Curitiba,
Brazil |
Figure 6: On-street busway system in São Paulo, Brazil |
Figure 7: Integrated trolley system in Quito, Ecuador |
Transit Design
Taking space away from motorists is the greatest political challenge
to introducing a new transitway, as mentioned above, but the greatest
design challenge is integrating the on-street transitway with surrounding
vehicular traffic, including traffic crossing the transitway on cross
streets and turning vehicles. If a new transitway also reduces the
number of available traffic lanes, it may result in secondary traffic
impacts by diverting traffic to other parallel streets, which may
then need to be modified to carry the additional traffic. Numerous
configurations for transitways within a street right-of-way are possible,
including in the center of the roadway, on one side of it, or on both
sides of the roadway (Figure 1).
The design of the transitway itself-including striping, curbs, barriers,
landscaping, distinctive paving, signage, lighting, and catenary for
light rail transit (LRT) or trolleybus-affects the overall character
of the corridor and may have either positive or negative impacts on
its surroundings. For example, the placement of the transitway and
its paving will affect the extent to which other vehicles intrude
into the transitway and detract from transit operations. Figures 2
and 3 illustrate different treatments of transit medians, including
paved and landscaped options. Curbside bus lanes are particularly
susceptible to intrusion of non-transit vehicles.
The location and design of transitway stations also pose specific
challenges in an on-street setting, particularly platforms, shelters,
amenities, and in-station fare control. On-street transit stops can
be as simple as a small island or more elaborate as with Curitiba,
Brazil's famous "tubo" stations shown in Figure 4.
Transit Operations
Transit operations in an on-street transitway also pose unique challenges.
Operating speeds, signaling, traffic signal preemption, bus platooning,
limited-stop service, and passing of transit vehicles within the transitway
can:
- Affect the quality of transit service
- Interact with surrounding traffic and pedestrians
- Impose specific design trade-offs due to
space constraints.
Signage and signals for transit operators, motorists and pedestrians
must be coordinated but distinct to facilitate safe operation. The
key challenge is to provide signs and signals that are readily understandable
to the public, including people who do not normally interact with
such on-street transit facilities.
Parking
and Pedestrian Circulation
On-street parking is invariably affected by the implementation of
a transitway, with some or all of it being removed to provide much
needed space. Where parking is retained, the available options and
their impacts on transitway performance depend on the placement of
the transitway within the street right-of-way. For example, curbside
transit lanes essentially eliminate the possibility of parking, while
transit in the median may allow parking either against the curb or
next to the transitway, as is typical in Curitiba, Brazil.
Because travel by transit inherently involves a pedestrian component
and a high-volume transitway concentrates pedestrian movement, the
planning and design of on-street transit facilities must account for
and facilitate pedestrian circulation and provide a pedestrian-friendly
environment. Improved sidewalks, enhanced crosswalks, station platforms
and bus loading areas can significantly affect pedestrian comfort
and the public's experience with the transit service. Passenger queues
also need to be accommodated to minimize conflicts with surrounding
pedestrian circulation.
Utilities
and Emergency Access
On-street transitways also have the following impacts on utilities
and emergency access:
- Underground utilities may need to be relocated
or alternate access may need to be provided.
- Catenary wires may need to be raised or relocated
because they can affect overhead utilities or pose particular
conflicts for firefighters, especially when adjacent multi-story
buildings might require access by ladder trucks.
- Access for emergency vehicles must be provided
for the benefit of both the transit facility and adjacent properties.
Examples of On-Street Priority Transit Facilities
around the World
Priority transit facilities using primarily on-street exclusive transit
lanes exist in a number of countries around the world, including the
following:
- Brazil. Brazilian cities have led the world
in developing on-street busways and have done the most experimentation
with different configurations and operating schemes. Arguably,
the city best known for its on-street priority transit system
is Curitiba.
Curitiba's innovative on-street busway system enjoys a high degree
of success because of coordination with overall roadway and land
use planning. Each busway forms the spine of a "structural
corridor" with parallel high capacity one-way arteries and
adjacent high-density land uses (Figure 5).
São Paulo, which preceded Curitiba in busway development,
now has four distinct on-street busway systems. Their different
features and the various schemes tried over the years make São
Paulo a veritable laboratory for the development of busways of
different configurations and passenger and bus vehicle capacities
(Figure 6).
Belo Horizonte and Porto Alegre also have developed urban busway
corridors, including significant on-street segments.
- Ecuador. Quito opened the
first segment of its Sistema Integrado del Trole (Integrated Trolleybus
System) in December 1995 (Figure 7). The system, which uses articulated
electric trolleybuses and high platform loading, has recently
been extended to a length of 22.4 km (13.9 miles). It carries
180,000 passengers each day.
A number of cities with transit systems that use off-street alignments
primarily include shorter segments in exclusive on-street rights-of-way.
These on-street segments are often in the downtown area to connect
off-street LRT or busway alignments in outlying areas. North American
examples include LRT in Boston, Massachusetts; Dallas, Texas; Denver,
Colorado; Los Angeles-Long Beach, Sacramento, San Diego, San Francisco
and San Jose, California; Pittsburgh, Pennsylvania; Portland, Oregon;
and Toronto, Calgary and Ottawa in Canada. Other cities with segments
of on-street priority transit facilities mixed with off-street alignments
include São Paulo, Brazil; Istanbul, Turkey; Manila, Philippines;
Birmingham, Manchester and London, UK; Cologne, Dresden, Hannover,
Munich and Stuttgart, Germany; and other cities in France and Germany.
The Promise of On-Street Priority Transitways
On-street priority transit facilities offer significant opportunities
in cities that are looking for new approaches to improving mobility
and the quality of life in a fiscally constrained environment. In
developing countries, on-street priority transit has special validity
because population pressures are acute, ridership and dependence on
public transit is substantial, and funds for more capital-intensive
responses is scarce.
In the U.S., where there is recognition that more cost-effective approaches
to improved transit are needed, the Federal Transit Administration
(FTA) has encouraged more consideration of options like bus rapid
transit, which often must be introduced into existing street corridors.
Bus rapid transit refers to a bi-directional transit service operating
in an exclusive or limited access right-of-way and making periodic
stops. It is attracting increased interest as a way to improve transit
service without the costs associated with rail.
Proper planning for on-street transitways requires a holistic and
multidisciplinary approach that combines consideration of transit
facilities and service, vehicular traffic, pedestrian circulation,
supportive land uses, station design, urban design, commercial and
economic impacts, and impacts on the community and
environment. |
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A Supervising Planner, Mark Walker has been
based in PB's New York office for nearly 15 years. Mark specializes
in transportation, pedestrian, and land use planning with special
expertise in the planning of transit alignments, modes, and station
locations; the design of transit stations, intermodal facilities,
and large transportation terminals; and the planning and design of
pedestrian networks and facilities.
[Ed. Note: This article was adapted from a paper and associated study
that were supported in part by the 1999 Research and Development Program
of Parsons Brinckerhoff Inc., and arose from a proposal for the 1999
William Barclay Parsons Fellowship. The author gratefully acknowledges
the support of Parsons Brinckerhoff Career Development and R&D
Program Committees.] |
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