Summary of DAG Presentation – October 1, 2012 Overview

Summary of DAG Presentation – October 1, 2012
In preparation for the DAG meeting on October 1st, we are providing DAG members with
a summary of the materials to be covered at that meeting. This includes an overview of
the schedule, MassDOT design package submittals, and description of modifications to
the design since we last met.
See Figure 1: Schedule through the start of construction - including DAG meetings during
each design phase.
25% Design and 75% Design Packages
A number of elements are identified in the 25% design package but will not show
detailed design until the 75% design phase. Primary among these elements are the
designs for the public space areas at the end of the Southwest Corridor, the MBTA Plaza
and Shea Square. Because of the high level of concern by the neighborhood for the
design of these areas and the complexity involved with each area being owned and
maintained by a different public agency, a DAG review process will be part of the 75%
design for these areas. The 25% design package will locate the area limits, fixed
elements and circulation paths, and will consolidate to the extent possible the space
remaining into contiguous areas that will maintain the greatest amount of flexibility for
the design. The question of programmed space will be addressed as part of the 75%
design development in a dialogue with the agencies that will be responsible for
maintenance. Designs for these areas contained in the 25% package should be considered
place holders for estimating purposes until a design that has received community review
has been developed.
Examples of other elements that will be developed in the 75% design phase:
Design Element
25% Design
75% Design
General tree and plant
More specific tree and plant
location and species
Regulatory signs
Wayfinding signs
Stormwater Management
Calculations and
Identification of
Development of design
General placement of street
Final placement of
streetlights and light
Traffic Signals
Traffic signal analysis
Traffic signal phase timing
and details
MBTA Elements
The design of the modifications to the MBTA’s Forest Hills Station (the Orange Line
headhouse, the Orange Line emergency ventilation shaft, the Commuter Rail vent grate,
and the upper level busway and canopy) are currently less advanced than the highway
elements. The DAG will review the MBTA elements as part of the 75% design process.
Modification to the Design
Route 39 Bus and Taxi Swap
The Route 39 bus pick-up and drop-off area is proposed to be moved from the north side
of the station (roughly its current location) to the upper busway on the south side of the
station. While this was initially planned as a temporary construction phasing relocation,
the consolidation of the Route 39 bus operations with the other buses on the upper level is
seen by the MBTA, the City of Boston, and MassDOT as beneficial enough to the overall
multi-modal performance of the project area to warrant its relocation as part of 25%
design. The taxi pick-up and drop-off areas on the east and west sides of the station can
be combined on the north side of the station.
While the distance traveled by the Route 39 bus is slightly longer, the impacts to the
overall route time are minimal. When compared to the bus operations at the north
side of the station, the AM peak the route time is reduced by eight (8) seconds and the
PM peak time is increased by twenty (20) seconds.
Bus operations are simplified. Dispatchers at two locations can be combined.
Transfers between the Route 39 bus and other buses connecting to Roslindale Center
and points south is easier.
Overall traffic operations are improved with buses traveling through major
intersections by conventional maneuvers.
Signal phasing at the Arborway and Hyde Park Avenue/Washington Street signal is
The relocation of the upper-level bus bays results in the bus exit shifting from the
intersection at South Street to a point roughly opposite Asticou Road. Mitigation
measures to reduce or eliminate headlight glare and illumination of buildings from buses
exiting at this location, such as fencing and vegetation along the west side of Washington
Street, are being explored as part of the design.
See Figure 2A: Route 39 Bus Relocation and Figure 2B: Potential Mitigation Concept
Second Left-Turn Lane at Shea Square
A number of modifications to the roadway design resulted from interagency review. One
of these was to reduce the length of the eastbound left-turn lane at Shea Square by adding
a second left-turn lane. This change cuts the previous queue length in half - from
approximately 400 feet to approximately 200 feet. A second receiving lane on Circuit
Drive is also included.
Left-turn traffic will be processed more quickly through the intersection. However, the
pedestrian crossing distance across the Arborway is increased by eleven (11) feet. This
eleven-foot distance equates to a 2.75-second walk (at a standard walking speed of four
feet per second). The additional time can be accommodated within the pedestrian phase
of the signal so that the crossing of the roadway can be completed in a single cycle. On
the east side of the intersection the median is widened by eleven (11) feet.
See Figure 3A: Single-Lane Left Turn, and 3B: Two-Lane Left Turn
4-Lane Washington Street
In June of this year a three-lane Washington Street was introduced between Ukraine Way
and the upper level bus exit. This three-lane configuration reduced the amount of
roadway pavement, while accommodating the necessary traffic, and provided additional
space for pedestrians, bicyclists and landscaping. However, based on City concerns that
capacity on arterial roads not be reduced, the three-lane configuration has been
eliminated and the four-lane configuration reinstituted.
See Figure 4: 3-Lane and 4-Lane Configuration – Washington Street
Bicycle Network Consolidated Off-Street
A significant amount of work has been ongoing with bicycle professionals regarding the
appropriate treatment of bicyclists through the corridor. Currently, the Casey Arborway
Project is showing the bicycle facility as an off-street bicycle path between the Arborway
Gate at the Arnold Arboretum on the west and Franklin Park on the east. The logic
behind this arrangement is to provide a facility that encourages use by bicyclists in an
area dominated by public open space, while reducing the overall amount of roadway
pavement. Commuter bicyclists, who may prefer an on-street facility, would share the
off-street bicycle path or ride with traffic in the street. At intersections, this off-street
path accommodates bicyclists with pedestrians in terms of street crossing and
The question was raised about the difference in time between a bicyclist traveling along
an on-street bike lane and an off-street bike path for the length of the corridor. To answer
this question an analysis was undertaken of the two options using the year 2035 traffic
projections. The analysis concluded that the off-street path would be slightly slower—
ranging from 0.4 minutes to 0.9 minutes depending on direction of travel and time of day.