Thursday, February 28, 2008

Going Below- Big Roads Below

Boston's I-93 Central Artery

Going below for highway design is to place the highway below ground by any of a number of methods to ultimately preserve the land above for other uses, including:

open cut highways designed to be subsequently covered

I-71 Fort Washington Way, Cincinatti, Ohio

cut and cover highways covered as a part of the same project that created the cut:

I-395 3rd Street Tunnel (1-95 Mall Tunnel), Washington, D.C., 3 blocks west of the U.S. Capitol Building

I-93 Central Artery/Tunnel Project, Boston, Massachusetts

BAB 100, Berlin, Germany

"The plans to extend Berlin's inner motorway ring from Tempelhof to Neuk├Âlln date back to the 1960s. They failed because of the considerable strain this stretch, which was planned as an open section at that time, would have placed on the neighbouring residential areas. In 1987 a decision was taken in favour of the shortest and most purpose-specific option: a 1.7 kilometre tunnel."

Lefortovo area Tunnel of the 3rd Inner Ring Highway, Moscow, Russia

Illustration: Park-Covered I-93 Central Artery

LANE COVE TUNNEL, Sydney, Austrialia

a key link in Sydney's orbital motorway network, connecting the Gore Hill Freeway with the M2. It will result in quicker journey times between the city and Sydney's north west. The project was approved by the Ministry for Planning in December 2002.

Bored tunnel, Around Paris, France
Versailles Tunnel

Single Level for Mixed Traffic with vertical clearance for trucks

Double Level for automobiles and vans under 2 meters in height

(2.55 verticle clearance)

3 lanes, @ 2.8 meter wide

A86 Motorway, Versailles, France

"Located at an average of six kilometres from the Parisian ring road, the A86 motorway forms the second ring road around Greater Paris. The motorway is aimed to reduce the traffic on the local roads, to relieve the Parisian ring road and to encourage travelling between the different areas in the suburbs.

The A86 West is the missing link of the "greater ring road", and is underground. 80% of the 78 kms are already completed. "

Filtration of Vehicular Exhaust in Road Tunnels

With the concentration of vehicular exhaust possible from placing vehicular traffic into tunnelways, road tunnel design has evolved with the innovation of ventilation systems to disperse vehicular exhaust. With the concerns regarding the release of such exhaust emissions into the general atmosphere, environmentalist groups overseas, particularly in Australia, have called for highway tunnels to be equipped with ventilation systems that include filtration (rather than simply dilution, as customarily practiced in much of the world, including the United States.

Road tunnels, urban air pollution and filtration - the issues.

Electrostatic precipitation: Valuable for removing particulate matter.

Used in Norway, Japan and Australia

New clean air legislation in Austrialia:

An Act to amend the Roads Act 1993 to require pollution filtration equipment to be installed and maintained that will remove particulate matter from air exiting the M5 East motorway tunnel, the proposed Lane Cove Tunnel and the proposed Cross City Tunnel.

Valuable for removing oxides of nitrogen and sulfate dioxide

Under experiential use in Norway, Austria and Japan is a gas purification system to remove from the air oxides of nitrogen as well as sulfur dioxide. Far from increasing costs, the Norwegian experience suggests that if air-cleaning technologies are included in the design from the beginning the overall expenditure is reduced.

Filtration equipped Tunnels: RX for reduced pollution

Road tunnels equipped with exhaust filtration would tend to reduce exhaust emissions into the general atmosphere by so diverting/accepting traffic, particularly if so providing regionally more direct routes, thereby accommodating greater human activity within a given developed region, and improving the economic competitiveness of older more built up, more pedestrian and transit friendly cities.

The use of filtration in new road tunnels has been advocated by environmentalist activist Bernard Saunders in the New York City Metropolitan region, for a new combined vehicular railway/highway tunnel for relocating the I-287 Cross Westchester Expressway underground

And for CO2:

Recycling Right of Ways and other existing swaths

This is the routing philosophy of minimizing the creation of all new right-of-ways that would bisect residential neighborhoods affect parkland corridors, via maximizing the use of existing right of ways and other cleared swaths for constructing grade separated new highways.

Such existing right-of-ways would include:

existing roads: particularly where an existing arterial has spawned adjacent strip development, lining the arterial with a generous zone of parking lots-

railroad-industrial corridors: where a RR has spawned an adjacent strip of industrialized properties, including such paved areas as loading docks, bus stops and parking lots, including those for utility vehicle storage.

power line and other utility line right of ways:

Because this design philosophy is meant to minimize dislocation and preserve public resources, it would not *necessarily* use what are known as "highway reservation corridors", if doing so meant employing wooded corridors which -- due to approval of real estate development projects -- become the sole neighborhood woods, as everything else is taken for subdivisions and local, non grade separate surface roads. Though portions of such "highway reservation" wooded corridors may be sufficiently wide, the narrowness or other factors regarding other portions might make a detour preferable, even if requiring the removal of houses, particularly those recently built when this potential conflict would tend to became more obvious.

Because such existing right of ways and other linear brownfield properties are limited in number and nature, preserving them for future use is essential. This does not mean that they must lay fallow, but rather that planning assign them such uses that avoid significantly increased future costs, allowing an evolutionary development over a time span of at least several decades that avoid the haphazard placement of expensive and immovable structures, especially residences, including those directly in the path, and those close enough to an existing structure -- such as a freeway retaining wall -- to increase the cost of its future replacement. Such uses would include multi-model transportation transfer points: e.g. sidewalks and pavement relating to mass transit access, bus bays and road, drop off (kiss & ride) areas, open air markets, town square type areas, along with movable and lower cost structures, such as kiosks, public information/service booths, movable vender stands and lower cost retail structures (perhaps with a 25 year amortization). This would utilize land, even providing revenue, while preserving design flexibility for future generations.

By preserving existing corridors and protecting them from misplaced real estate development, we use land more efficiently, ultimately allowing its use for multiple purposes, and reducing or eliminating the need for paving through much in the way of wooded suburban highway reservation corridors, hence making it more likely they will forever remain as wildlife corridors. By preserving urban brownfields in particular, we preserve potential for future projects to improve the transportation and greenspace networks via burying railways and highways beneath new linear promenades for bringing communities closer to each other locally and regionally with shorter more direct routes.

Historical Examples:

Larchmont (Westchester County), New York

I-95 New England Thruway: where the use of the previously acquired wooded corridor for the not-to-be-built Pelham-Port Chester Parkway, would take a detour through the parking lots along the Metro North New Haven RR line which previously served as the railbed for the defunct New York Westchester and Boston RR (1912-1937), with a 1930s parkway bridge now amidst a city park.

Washington, D.C.

I-66 North Leg West segment of the Inner Loop: new open depressed swath paralleling Florida Avenue-U Street, versus a cut and cover tunnel beneath K-Street

Brooklyn, New York

Cross Brooklyn Expressway: new swath paralleling Bushwick Avenue (I-78), versus double decked elevated or triple decked depressed atop or within the existing 50 foot wide LIRR Bay Ridge RR right of way (I-287 or I-878)

Examples of Why:

Avoiding Forseable Conflicts


Foreseeable conflicts between transportation needs and real estate development occur when government entities involved with planning matters fail to consider long term needs when they approve real estate projects so situated to significantly raise the costs of future transportation projects, with forseeability be greater for those involving technologies already in widespread use. Such situations include real estate development placed directly in the path of a new or improved roadway, and those placed close enough with a design that does not guard against increasing the costs of future transportation infrastructure construction, such as new structures placed alongside an existing retaining wall that would have to be shored up to replace the existing retaining wall.


  • Greater Mixed Use of Land via Cataloging existing corridors and right of ways, including adjacent properties.
  • Acknowledging Long Term Needs and Existing and Foreseeable Future Technologies
  • Ensuring that real estate development respect transportation corridor setbacks for maximizing its potential via not placing relatively expensive structures too close, hence minimizing/avoiding future conflicts, such as the demolition of apartments.
  • Leaving room to facilitate future transportation infrastructure construction with less disruption and lower cost, for instance leaving space to construct new slurry walls designed for decking over a roadway, along with some capacity addition, including better ramps and additional mainline lanes at traditional chock points for reducing congestion.
  • Long Term Planning with more evolutionary and modular Designs
  • Greater "bang for buck" with design consideration for future improvements consolidating and reducing costs per benifit.