The proposed new Tappan Zee Bridge—expected to be complete by 2017 to the tune of $5.2 billion—was given the go-ahead after a tunnel option was deemed unsuitable, officials have said.
Experts studied the tunnel alternative before . The tunnel, officials said, would likely have consisted of five underground tubes, each with two lanes. Another tunnel option was one underground unit with two chambers.
The tunnel would have stretched seven miles and required "extensive shoreline and in-water work," reports said.
The concept was dismissed for a number of reasons, mainly due its cost and effect on the region's environment. Experts noted the tunnel "would take longer to construct at a higher cost," and the required bells-and-whistles—like ventilation—would impact nearby shorelines and swamps.
Another cardinal reason for its dismissal? An inability to accomplish its main goal—better transportation. Traffic flow would be often impaired, trucks would have trouble tackling steep grades and emergency vehicles would have longer response times, the report notes.
A tunnel would not allow for pedestrian and cycling paths either, a planned addition to the coming crossing. Some politicians want to take the plan further and , but Thruway officials and the Governor have yet to endorse the idea.
Still, the tunnel option retains supporters—mainly due to the possibility of reducing pollution. The Tappan Zee Bridge sees approximately 135,000 vehicles daily, and Richard Kavesh, Nyack's mayor, that transitioning that traffic underground would make for cleaner air.
Residents are also upset about the proposed bridge's lack of mass transit options. Although installing rail and bus lanes would just about triple the cost and bring the price tag to $16 billion, many Rocklanders .
"We do not want the bridge of 1955, but the bridge of 2055," said Jen Laird-White, Nyack's deputy mayor, at a . "It will be expensive, it will be difficult to achieve... but we need to bring back the money for mass transit."
The main advantage of an immersed tube is that they can be considerably more cost effective than alternative options – i.e. a bored tunnel beneath the water being crossed (if indeed this is possible at all due to other factors such as the geology and seismic activity) or a bridge. Other advantages relative to these alternatives include: Their speed of construction Minimal disruption to the river/channel, if crossing a shipping route Resistance to seismic activity Safety of construction (for example, work in a dry dock as opposed to boring beneath a river) Flexibility of profile A tunnel would be much friendlier environmentally to both shores and rapid transit could just take the form of a parallel tunnel devoted soley to rail transit. It could be much cheaper to assemble and then float into place when complete. Where are the numbers that say a bridge is cheaper, especially since the bridge would probably have to be floated on pylons like the current one is. Most people don't know that the current bridge has a unique aspect in its design in that the main span is supported by eight hollow concrete caissons who's buoyancy is maintained by immense pumps that must be maintained and adjusted around the clock.
Isolating the community from the thruway could be the best thing to happen since the bridge was built. The current bridge could be maintained, only used by emergency vehicles...and maybe jitney service to the Tarrytown station. Start a pedicab business like the one in Time's Square. Loads of possibilities......