Merits of Surface and Underpass Options

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19 March 2017
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Rutherford Ave./Sullivan Square Design Project
Comparison Chart
Based on February 28, 2017 Presentation in Charlestown

At Grade (Surface Plan) Design
North Gateway/Underpass Design
Urban Design:  Allows for the creation of a person-centered Sullivan Square with green space, buildings and plaza as shown in 2013 Sullivan Square Disposition Study.  Leverages value of urban design work already completed by the City.  
Preserves space for SS Disposition Study planned development sites.





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Urban Design:  No urban design study has been presented.  Green space and housing development in the area within the existing rotary are difficult to build on the proposed decks over the underpasses.  Space for cost effective development is eliminated along north underpass ramps. Green space is greatly reduced at south ends of underpass ramps.  Underpass lanes effectively occupy entire infield of today’s rotary wasting valuable space. Buildable parcels are small compared to roadway widths.  Two-way Maffa Way and Main Streets require more width than one-way streets in At Grade design and contribute to a roadway dominated Sullivan Square.
Consistency with City Planning Goals: Safe multimodal surface streets are consistent with good planning practices and City of Boston goals (Imagine Boston, Go Boston 2030, Vision 0, Complete Streets).  They provide mobility for all people, good access to transit, livable and safe streets and encourage transit-oriented development.  
City Planning Goals: Emphasis on accommodating through traffic with a complex space consuming roadway design and a missing connection at Arlington Avenue make achieving the City’s Long Range 2030 goals difficult.
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Cost:  Parcel development costs will be significantly less where air rights development is not necessary.  Building construction will also be less expensive.

Could leave funds available for well developed green spaces.
Cost:  Underpasses with or without decking are much more expensive to build and maintain.  Buildings above them will be expensive and difficult to build and lease. Because of the complexity and expense, development above underpasses often does not happen.
Linear Open Space:  Linear park with 40’+ depth for cycle tracks, walkways and programming is created on the neighborhood-side of the street  This creates an esplanade-like amenity with enough area to include green infrastructure/ storm-water cleansing/ flood mitigation.
No Continuous Linear Open Space Created:  Open space is restricted to a cycle track and walkway alongside the south ramps of the underpasses on the neighborhood side.  No opportunities for additional amenities will be possible there.
Traffic Pattern: Predominant existing regional traffic pattern along Rutherford Ave is maintained. Traffic will flow more easily and effective traffic signage can be more easily established.  Traffic lights and the distribution of traffic provide for predictability and make streets safer. The entrance to Charlestown on Main Street can be more easily traffic-calmed.
Traffic Pattern: Emphasizes direct roadway connection between Everett and Downtown Boston (through existing underpass alignment) and between Somerville and Charlestown through new straight line route to and from historic Charlestown proper.  This route will encourage unwanted through-traffic on Main, Bunker Hill, Medford, and Chelsea Streets.   ​
Road Geometry: Clarity of the simple grid layout creates better traffic flow.





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Complicated Road Geometry:  Creates complicated route to Everett from I-93 N off-ramp at Cambridge Street. Route takes vehicles along Alford Street West to an “S” connector (like a level off- ramp with tight curves) over underpass portal. That connector leads to Alford Street East and the Alford Street Bridge. This is a poor entrance to Everett and Wynn Boston Harbor from I-93 N.
Sullivan Square: New Sullivan Square Park becomes symbolic gateway into Charlestown from the north comparable to City Square Park gateway at the south.

Instead of the North Gateway “X” roadway intersection in the Underpass Design, two additional parcels are created and contribute to the livability of the area.
North Gateway: Plan creates “X” intersection with single lane for “left turn” on route leading into Charlestown from Broadway/I-93 S off ramp. This is the main route from I-93 S to Everett and uses the same “S” connector to the Alford Street Bridge and Wynn Casino as the Cambridge Street I-93 N off- ramp.
The “X” Intersection will be a choke point causing traffic to back up into Somerville and onto the I-93 off-ramp.
Bus Access to T Station: Nos. 92, 93, 104, 105, &109 bus- only lane provides access to the T station and operates in the same direction as existing traffic.
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Bus Access to T Station: Nos. 92, 93, 104, 105, &109 bus- only lane operates in the opposing direction on short two way section of Main Street in “X” intersection.  This creates a confusing and hazardous condition.
Complete Streets: Planned but not shown on all drawings.
For comparison purposes design plans of the At Grade solution need to be drawn to the same level of detail as the North Gateway/Underpass Design plans.

Complete Streets: Shown in drawings. Parking is not shown.  As plans progress applicable complete street standards need to be agreed upon for all the streets in the selected design.

Traffic Projections for this project are based on current trends based on number of vehicles.  Projections have not yet included improved rapid transit, multiple occupancy vehicles like shuttles, improved bus service or improved use of pathways by bikes and pedestrians.  Also, they do not include considerations for autonomous vehicles and other technological advances or the disappearing traffic factor used in Somerville’s McGrath Boulevard Project and the new USDOT Rule for measuring congestion that considers people not just vehicles.  These improvements will result in reduced vehicular traffic demand and should be incorporated in the Rutherford Avenue/ Sullivan Square Design Project to determine adequacy of planned streets.

Traffic Projections for this project are based on current trends based on number of vehicles.  Projections have not yet included improved rapid transit, multiple occupancy vehicles like shuttles, improved bus service or improved use of pathways by bikes and pedestrians.  Also, they do not include considerations for autonomous vehicles and other technological advances or the disappearing traffic factor used in Somerville’s McGrath Boulevard Project and the new USDOT Rule for measuring congestion that considers people not just vehicles.  These improvements will result in reduced vehicular traffic demand and should be incorporated in the Rutherford Avenue/ Sullivan Square Design Project to determine adequacy of planned streets.
Climate Resilience – Flooding Potential:  With the entire roadway system at grade, flooding on this important evacuation route corridor can be minimized. ​
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Flood Prone: Underpasses do not prepare area for flood prevention in a corridor that is already prone to flooding. Current flood maps, much less the 100 year storm flood, make this design exceedingly vulnerable.  The underpass design is already very susceptible to large tide and SLOSH events.  This critical evacuation route would be inundated when most needed.  ​
Pollution/ Human Health:  At grade option provides near- continuous planting buffer along the east side of Rutherford Avenue with opportunities for phytoremediation of urban air pollutants.

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Pollution/ Human Health:  Tunnels have been shown to exacerbate urban air pollutants because they are concentrated.
Underpasses are also more pollution prone due to reduced air circulation and concentration of contaminants from cars, trucks & busses.
No Echo Chamber Created: All traffic will be at grade with no hill climbing required.  Noise will be evenly dissipated.
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Noise Reverberates:  Underpass creates echo chamber, exacerbating noise pollution in the underpass and at the portals.  Truck traffic and braking system noises are amplified.  ​
Number of Lanes to Cross at Surface:  This number is hard to determine without adequate drawings.

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Number of Lanes to Cross at Surface:  The number of lanes to cross at the surface seems to be about the same as in the at-grade option.  A wider footprint of asphalt per lane is required within the boat section.
Crossings:  Cross streets are possible anywhere along the length of Rutherford Avenue.



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Crossings:  Crossings are provided by bridges over underpasses at Sullivan Square and Mishawum Street.
Shortened underpass ramps allow access to D street (Hood Park), A street, and Community College south of the Square. No crossing is provided at Arlington Avenue north of the Square.
Arlington Avenue & Ryan Playground Access:  Design provides important Arlington Avenue access to current MBTA bus yards and potential transit oriented development in the area. This facilitates Imagine Boston 2030 planning objectives.
Ryan Playground parking located opposite Arlington Avenue intersection is easily accessible.
Arlington Avenue and Beacham Street form an alternative route for Wynn traffic heading via Mystic Avenue in Somerville to I-93 N and I-93 S (via the planned U turn east of Route 28)
Arlington Avenue & Ryan Playground Access:  
Arlington Avenue cannot be reached from Rutherford Avenue northbound. 
Access to Ryan Playground is provided from Alford Street East.
Egress from Ryan Playground is provided via an opposite direction lane on an unusual two way section of Alford Street East (east of underpass ramps). Vehicles must turn into oncoming traffic (with a stop sign?) to access the lane. Seems unsafe.
On Street Parking:  Provides on street parking, a benefit for residents and business that also improves pedestrian safety because autos form a barrier between pedestrians and traffic.
Appropriate locations for parking need to be identified.
On Street Parking:  No on street parking appears in the design.  Appropriate locations would need to be identified.

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Speed / Safety:  Overall feel of Rutherford Ave. is less like a highway since underpass ramps do not divide the east and west sides.  Streets accommodate adequately sized parcels to allow beneficial development.  Overall quality of the design encourages active city streets as anticipated by the SS Disposition Study.

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Speed / Safety:   “T” intersection at south end of underpass helps to regulate traffic speed and allows crossings elsewhere.  
However, focus of Sullivan Square and Rutherford Avenue in this design is regional traffic movement rather than city streets allowing regional traffic through.
Confusing road geometries are not conducive to safety and make accidents more likely.
Smaller Central Park Space:  New gateway Sullivan Square Park could be built on available land on grade. Park would be more convivial because of its location and activity and would be attractive to walk-though.
New park replaces the 19c. Sullivan Square Park eliminated by the circle/underpass/fly over construction in 1952.  
The surface design allows for building development, on-street parking and slower traffic, making green space quieter and more conducive to walks and lingering to socialize.
Larger Park Space:  Larger Sullivan Square Park (not shown) could be built over tunnels (if funding is available and tunnel ventilation Is OK.)  Location is less desirable since it is not as central to new development or close to the original Sullivan Square.





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