Study: Tunnel Would Cost $1.3B More Than Signature Bridge

FDOT evaluated a proposal to put a portion of I-395 and Biscayne Boulevard underground, instead of building a Signature Bridge. The results:

  • The tunnels would cost $1.3 billion more than the Signature Bridge
  • Both Biscayne Boulevard and I-395 would have to be locked down during Hurricane events due to flooding concerns, closing vital evacuation routes
  • Metromover would need to be reconstructed, with associated cost and service disruption
  • Biscayne Boulevard and other nearby streets would need to be closed during construction
  • Pedestrian crosswalks would be eliminated in some areas near the tunnel. Nearby streets would also need to be elevated, inhibiting access
  • Likelihood of contaminated soil during excavation. Area was previously occupied by the Belcher Oil Terminal & Tank Farm
  • Construction would be delayed an extra five years for a Supplemental Environmental Impact Statement

FDOT’s Gus Pego will present the study, along with an update on the Signature Bridge, to Miami commissioners next week.


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Another Anonymous

The Boston Big Dig (tunnel that suppresses I-93) is a good case study for this in cost overruns and its effect. Although much larger than Miami I-395 it went from an estimated $2B to over $14B. The lowering of I-93 stitched the city and its downtown together and connected the finacial district to the North End. The Real Estate values shot up enormously and far more Real Estate development has ensued that had created more value than the cost of the project. Downtown Boston now shines. This small portion would connect Omni and Overtown to the Entertainment District and make the museums and the Arscht Center that much more accessible and relevant. If a Baylink could be tied in to this, then in effect this would be the new heart of Miami. Furthermore, MiamiWorld and the potential Miami Innovation Center near by would also grow because this section of Miami would have the critical mass, the lore, the connectivity that you see in great cities. If it worked for Boston and helped its Financial District connect to the North End and Seaport, it would do wonders for Miami. Note that Boston has developed an Innovation District at the Seaport where… Read more »


Exactly. Our local politicians are scared to do anything really worthwhile for future generations. We haven’t seen any since the 1970’s that came up with starting a rail line. Unfortunately the following politicians sucked and screwed everything up. Now all we do is piece meal projects. No visionary politicians around here anymore. No forward thinkers.


Actually this plan would further divide the waterfront from the rest of the city because of the biscayne highway.


The tunnel is still the ONLY solution to the problem. The ‘bridge’ does not fix anything; it may have form or beauty depending on personal perception but has no function…it is still a bridge and we already have a bridge that devides biscayne in two. With the new bridge, we are going to have a new ‘gateway’ but the problemactic will be the same.


should still be done. long term – its the best solution for the city.


We should be investing in tunnels under the Miami River, which is still an active industrial port. Multiple times an hour the drawbridges raise to allow cargo ships to pass, wreaking havoc on the traffic in our downtown urban core. Brickell Avenue should cross under the river and connect to the CBD, much like the rendering in the proposal from the FDOT. The existing bridge would still be used for bicyclists and pedestrian traffic. The same should be done for the Miami Avenue bridge. We need to be investing our resources in areas that will make an impact on the every day lives of our citizens. Building a “signature bridge” does nothing more then stroke the egos of the politicians.


It’s funny. I had the chance to pass by that place yesterday and as I was walking out of the Knight Center, I saw that the bridge was raised. Man, man, did the traffic get so bad that it looked like a parking lot. Not only that, people were honking the whole time. I think I saw two people screaming at each other from their cars. You’re right. Tiber Hollo did predict this. Now, will it happen? I think it will happen when all other options have been exhausted.


I wish you would have put your name on your comment because you deserve credit for making some very good points. I completely agree that a tunnel under the Miami River is more important than the one being discussed in this article. The traffic between Brickell and Downtown will continue to increase as the years go by and more and more sky scrappers are built. This problem needs to be addressed sooner rather than later and bridges are not the answer.


While waiting to build a tunnel under Miami River,can we at least clean that F&$#@% bridge.It looks horrible.


The drawbridges do suck for traffic, but most of all they are a huge hazard for pedestrians and cyclists. There have been numerous terrible accidents involving cars heading up the incline of the bridge and striking cyclists that they could not see.

These tunnel ideas are all great, but expensive and beyond the scope of what our idiotic government can do. An easier project that I would LOVE to see is a designated pedestrian/bike “bridge” built across the river. This could be something as simple and beautiful as a swinging pontoon bridge like the one in Willemstad, Curacao. It would be a perfect extension of the Underline, taking the linear park across the river and up to the new Central train station/World Center.


Absolutely absurd proposal. Only I-395 needs to be underground, not Biscayne! In fact putting Biscayne underground is a huge negative. This rendering does not show the extensive tunnel entrances which would greatly disrupt the urban fabric and completely block pedestrian crossings at place where they are most needed! Look at the US 1 tunnel in Ft. Lauderdale to understand what this would do the surrounding area.

Biscayne BOULEVARD needs to be a true boulevard with wide sidewalks, slower traffic, and numerous crosswalks…e.g. Pennsylvania Avenue, Champs Elysee.

Where is the common sense urban planning and design in Miami?????


Finally, someone else who gets it. I’ tried saying this earlier and was downvoted.


Baylink should be a priority, not a tunnel


Do both it’s not either or.


We obviously should build the metrorail over to to the beach as well as expand the metrorail to the Homestead area and to the Aventura Mall area. The traffic as it is, is already annoying and causing the economy to slow down as time spent on a highway is time spent not working, reading, or doing something productive. It also causes health problems as I have read many times.

However, the tunnel should also be built but only after the Baylink, and metrorail expansions to the north and south of Miami-Dade.

In the end, expand public transit as it is the only viable solution to the traffic problem in Miami. Build the tunnel after the expansion and the areas around the tunnel will see an increase in pedestrian activity, an increase in economic activity, and an increase in real estate values. Who knows? We might even see more real estate development around the area.


Who is paying for it?


Original plans were to run I-395 under Biscayne Blvd not as a Tunnel but as an open cut concept. All other streets would have remain at ground level with no need to be closed down in case of a hurricane. The study was done on the concept of making I-395 and Biscayne Blvd into tunnels (see the renderings). This is for sure more expensive and difficult to do….I guess whoever paid for the study had an stronger interest on that Signature bridge being built.


FDOT sounds like they really want their darn bridge…

The tunnels would cost $1.3 billion more than the Signature Bridge.
(Ok twice as much as the bridge but also 100x better)

Both Biscayne Boulevard and I-395 would have to be locked down during Hurricane events due to flooding concerns, closing vital evacuation routes
(I would hope that no one is driving across a bridge to Miami Beach during a hurricane anyway)

Metromover would need to be reconstructed, with associated cost and service disruption
(Metromover has to be constructed in the bridge plans also)

Biscayne Boulevard and other nearby streets would need to be closed during construction
Pedestrian crosswalks would be eliminated in some areas near the tunnel. Nearby streets would also need to be elevated, inhibiting access
(Street closures would happen during the bridge construction also. Pedestrian walkways an traffic flow would eventually be enhanced with the tunnel)

The case study with Boston’s big dig is an excelled example. Will it cost a lot of time and money, yes. But the benefits economically and transportation wise would be even greater.


This proposal is flawed. Biscayne should be at grade with only 395 below grade. It will still cost a lot, but less than 1.3 billion more than the bridge.


This proposal is worse than what currently exists. This turns Biscayne into a highway south of 395 and further isolates Museum Park. Residents in the towers across the street would not be able to cross at all.

Is anyone really surprised by this design? FDOT loves their highways. This proposal would be doing the city a dis-service.


I don’t want a pretty bridge. Why is Miami trying to find it’s ” signature something “… Can’t we just expand metro rail to have 6 more lines ? connecting baylink Miami beach, running it west to FIU, then to homestead and up to Aventura and Sunlife stadium. Artery and Veins of the metro running everywhere. I don’t feel like driving anymore.


“Can’t we just?” The answer would be no. Not unless you’re aware of some magical funding genie who can make billions of dollars appear out of thin air. Not happening.


Whatever the cost, do it.


Yes and no. Do it but do it in an economical way that will allow us to invest in other resources, transit, education, and so on.


Whatever the cost ? lol….I will never elect you.


still the best option!!!


It would pay for itself. The value of the freed land that could be sold to developers should cover extra cost.


How about open cut concept covered with concrete panels and grass,creating a cheaper version of a tunnel .lBiscayne Blvd. stays the way it is.How expensive is that?


Wanna make a difference? Go be heard.. Posting here won’t change anything and this one change worth giving our two cents worth. Can’t go backwards once it’s decided. I’m going

Yet Another Anonymous

Wow that looks good tho.


I hate stupid people. Therefore, I hate FDOT.


Why are they not listing any of the positives?


It is sad that only the people that visit this forum are the only ones getting informed on this ridiculous project; what about public in general??? FDOT is not really considering the option where they partially cover I-395 below grade. Can we do anything???


You can email the City Commissioners. They do respond if enough people care but the problem is that not enough people care enough to email their commissioners.


Possibly the most amateurish sketches I have ever seen. Was this a class project from some Middle School?


I love how FDOT evaluates the plan for the tunnel but paid no notice for Miami commissioners’ calls for the money to go to baylink and other mass transit projects instead. FDOT really needs to get their priorities in order


The study is from 2014. Hasn’t the cost of the bridge gone up since making the difference smaller?




The problem is not between choosing between a bridge or a tunnel. The issue is about connecting the city. A bridge is not needed and a tunnel is too expensive. A third way is something that is happening in other urban centers. For example in Tornoto they are Turing the area under a highway into an art park,


This would be amazing. i hope it happens. we should put all of 95 and 195 that runs through downtown and brickell underground. we could create more green space and end the divide of our communities.


Tunnel would be awesome but is clearly and unfortunately not happening. There is a third option that I haven’t really heard discussed: converting I-395 to an at-grade boulevard with a circle at Biscayne. Many will look at that and say that it’ll be a traffic nightmare but plenty of European cities do this and have devised very effective traffic easing designs. This will unite downtown while maintaining right of way and will be certainly cheaper than either option. Not sure if this is the right answer but it’s mystifying how it hasn’t even been discussed.


European cities do this with avenues and boulevards… not major highways