Tunnel replacements

[Mergingtraffic]

CT is proposing to build a new tunnel which will be temporary so they can rehabilitate the current twin tubed West Rock Tunnel in Hamden, CT.

To me, it seems silly to build a new 3rd tunnel only to shut it down again after work on the main tunnel is finished.  Now, if the third tunnel were to alleviate congestion permanently then I can see it.  If CT-15, which the tunnel is on were to be widened or something then I'm all for it.

Do other states face this?  I don't see NY/NJ building a new tube to fix the Lincoln Tunnel or PA doing this to fix the pA turnpike tunnels.
Any other options?

http://wtnh.com/2015/12/15/is-malloy-planning-tunnel-to-no-where/

[Pete from Boston]

Has there been a travel demand study?  Where people traversing the tunnel begin and end their trip?

The "24-hour traffic jam" statement is exaggerated, I'm just curious how much. 

How able is the governor to "clear the way" for a project like this?

[jeffandnicole]

CT is proposing to build a new tunnel which will be temporary so they can rehabilitate the current twin tubed West Rock Tunnel in Hamden, CT.

To me, it seems silly to build a new 3rd tunnel only to shut it down again after work on the main tunnel is finished.  Now, if the third tunnel were to alleviate congestion permanently then I can see it.  If CT-15, which the tunnel is on were to be widened or something then I'm all for it.

Do other states face this?  I don't see NY/NJ building a new tube to fix the Lincoln Tunnel or PA doing this to fix the pA turnpike tunnels.
Any other options?

http://wtnh.com/2015/12/15/is-malloy-planning-tunnel-to-no-where/

Yes, other states face this.

Actually, the PA Turnpike is looking at bypassing or replacing at least some of the tunnels still in use on the PA Turnpike.

And while there's no immediate plans I know of with the PANYNJ highway tunnels, NY & NJ are trying to secure funding to build a new Amtrak tunnel under the Hudson in order to shut down the original one to rehabilitate it.

[cpzilliacus]

Colorado DOT built a new tunnel (they will keep in service) as part of a freeway reconstruction project (which adds toll lanes) on I-70 at Idaho Springs between the Eisenhower Tunnel and Denver.  Not sure it is what you were looking for, but the scale of the project looked pretty massive when I drove by there in 2014.

Recent Denver Post article: Idaho Springs residents just want construction on I-70 to stop - The $78 million tolled express lane, which stretches 13 miles from Empire to Idaho Springs, will be open 73 days a year

[Chris]

In some mountainous areas, a mountain tunnel at high elevation may be bypassed by a new / wider tunnel at a lower elevation.

A notable example are the Sasago Tunnels in Japan, located on the Tokyo - Kofu route. The first tunnel was built in 1938, which was bypassed by a new tunnel at a lower elevation in 1958. It was then replaced by the expressway twin-tube tunnel in 1977.

The Baytown Tunnel near Houston was replaced by a bridge in 1995. It was replaced because the Houston Ship Channel needed to be deepened.

[DrSmith]

My understanding of the train tunnels for PANYNJ is that a new tunnel will be built and then rehabilitate the old tunnels.  But the end goal is to actually have an additional tunnel in the end for increased capacity as well as doing the required maintenance on the current tunnels. Building the new tunnel first allows for current capacity to be maintained while closing the older tunnels one at a time to perform maintenance.

[kkt]

In some mountainous areas, a mountain tunnel at high elevation may be bypassed by a new / wider tunnel at a lower elevation.

A notable example are the Sasago Tunnels in Japan, located on the Tokyo - Kofu route. The first tunnel was built in 1938, which was bypassed by a new tunnel at a lower elevation in 1958. It was then replaced by the expressway twin-tube tunnel in 1977.

The Baytown Tunnel near Houston was replaced by a bridge in 1995. It was replaced because the Houston Ship Channel needed to be deepened.

There was an old tunnel through the Berkeley Hills between Berkeley and Orinda, partway up the hill, above where the Caldecott Tunnel is now.  The Caldecott itself was built in three bores for road plus a bore for BART.

Gotthard Tunnel, then the Gotthard Road Tunnel, now the Gotthard Base Tunnel will open next year.

[Pete from Boston]

My understanding of the train tunnels for PANYNJ is that a new tunnel will be built and then rehabilitate the old tunnels.  But the end goal is to actually have an additional tunnel in the end for increased capacity as well as doing the required maintenance on the current tunnels. Building the new tunnel first allows for current capacity to be maintained while closing the older tunnels one at a time to perform maintenance.

Not the PATH tunnel but rather the Amtrak/New Jersey Transit tunnels.