Tunnel Tour questions:
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Aside from cost, what are the downsides
of tunnels? How about advantages?
The website of The Automobile Association
Limited of England has the following list of tunnel downsides:
- Higher building costs and difficulties
of cost control during construction
- "cut and cover" tunnels can
be disruptive during construction
- good standards of daily operations required
- ongoing operational costs
- underground junctions difficult and potentially
- siting of portals and ventilation shafts
needs to be carefully selected
There are probably other disadvantages to
urban tunnels not included on their list. Examples are safety
issues - emergency vehicle access, fire protection, emergency
egress, and perhaps claustrophobia issues for some motorists.
The Automobile Association Limited of England website also
has a list of advantages to tunnels. Here are a few of my
- while vehicle emissions on surface streets
flow straight into the air, harmful pollutants in tunnels
can now be collected before ventilation and "scrubbed"
near clean using new technologies
- techniques of tunnel construction have
made major advances in recent years - in some locations,
tunneling can even be cheaper than surface constructions.
Real costs are falling at around four per cent per annum
- advanced countries around the globe,
in town and country, are increasingly willing to pay the
cost of retaining landscapes or reclaiming surface streets
by moving strategic roads or major arteries underground
at pinchpoints, sometimes over long lengths
- the accident rate in tunnels worldwide
is half that of inter-urban roads and even less than half
in urban areas
Why doesn't this plan include burying Storrow
Drive behind the Esplanade?
If the section of Storrow Drive behind the
Esplanade were ever buried, it would be a cut-and cover tunnel
(similar to the existing tunneled section of Storrow Drive
already buried to the north of Back Street between Arlington
and Berkeley Street, in the Back Bay). That effort would be
a different technology and venture than what is proposed here.
The proposed Freshgate Tunnel would be a deep-bore tunnel.
It could be built and opened with far less interference to
existing traffic flows during construction than burying Storrow
Drive behind the Esplanade would entail. Also, such a venture
at the Esplanade would seem to be beyond the purview of Harvard
University – the proposed funding source of the deep-bore
tunnel in this vision. Burying the existing roadway between
the Esplanade and the Back Bay may be a good idea, but it
is not the purpose of this website to advance it.
Shouldn't this proposal also include public
transportation ideas along with an automobile tunnel?
transportation improvements definitely ought to be included
in the mix of ideas to consider. Here are just two of many
public transportation schemes worth pondering:
- A larger diameter tunnel with sufficient
room for a third level for light rail vehicles.
For instance, the Green Line could have yet
another western leg, beginning beneath Charlesgate (just to
the east of Kenmore Square), and running within and beyond
the Freshgate Tunnel all the way to the Red Line's Alewife
Station in west Cambridge, about ½ mile from Fresh
Pond. Here is a cross-section of what the tunnel might look
like if a Green Line extension were included:
This Green Line extension would have intermediate stations
along the Freshgate Tunnel route - perhaps at MIT, at Western
Ave, at North Harvard Street, at Mount Auburn Hospital, or
at Fresh Pond.
- A new, mini surface system of public transportation
along some of the routes where parkways have been removed.
One of Harvard University's Allston Initiative
Progress Reports described such a mini-bus transportation
system called the SMRTram. A unique feature of the SMRTram
is that the mini-busses run on a single narrow roadway in
both directions. The mini-busses cross each other only at
the stations. This narrowness of both the busses and the roadway
makes SMRTrams relatively unobtrusive.
SMRTram system could run along the entire route where Storrow
Drive has been turned to parkland - from Soldiers Field to
Charlesgate. The SMRTram system would provide easier public
access to the new parklands where the roadway had been (important
for people with disabilities, the elderly, etc.) Also, for
commuters and motorists who would miss the pleasant views
along Storrow Drive, a SMRTram would provide an even more
pleasant and safer means of transportation along the banks
of the Charles River Basin. Here is what the SMRTram looks
Here is another resource for public transportation
options along the Charles River: Ed Nilsson, of Nillson+Siden
Associates, has developed a visionary scheme for the Charles
River that proposes extension of the Blue Line along the Charles.
(For a link to a website showing this vision, click HERE).
Wouldn't the construction process mess
In this vision, the entire deep-bore tunnel
(and all of its entry ramps that are either deep-bore ramps
or in places where traffic would be unaffected) would be totally
completed before any work to change existing roads even begins.
Traffic problems would be incurred only during construction
of the top ends of the new ramps and interchanges. All the
rest would already be completed. Still, the construction process
would definitely mess up traffic for a while, but not as badly
as the Big Dig has.
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