Boston's "Big Dig"

Image above depicting the before and after of one of the major parts of the Big Dig ("Before and after the Big Dig" 2017) Reproduced for Educational Purposes Only under Fair Use.

Boston was a city founded in the 17th century and expanded upon over the course of centuries. As a result, much of the infrastructure was designed for cows and horses in mind (narrow roads) and thus would prove difficult for the transition to cars in the modern era. 

Shown above is Beacon Hill, one of the historic districts of the city filled with brownstones and cobblestone roads. Even some gas lamps still light the roads at night preserving the historic beauty. While this path is not a prime example of the majority of roads in Boston, much of Boston contains roads not much wider, creating one way streets and bottlenecks.

As you can see much of Boston that we see today was added on over the centuries through landfill. For example a portion of Beacon Hill was used to fill in several parts of Boston. Landfill would prove to be an issue later.

As more American consumers could afford cars toward the mid 20th Century, the issues with the narrow roads became more and more prevalent.

Boston went through a series of highway construction projects and upgrades starting in the late 50s with the introduction of major highways to cities, and again in the 60s with the Sumner and Callahan connecting downtown to the airport under the harbor (Flint 2015). The major highway running through the center of the city, I-93, was coined the “Central Artery” (Flint 2015). 

Above we see the highways and tunnels produced as a result of the 50s and 60s. The Sumner and Callahan Tunnel crossing the harbor created a direct link to the airport from Downtown Boston. However, much of the highways were above ground or elevated especially those going through the center of the city.

While this video is not from the original construction of the Callahan Tunnel, done in the late 1950s and opening in 1961, this shows what the Callahan Tunnel looks like (Boston Globe 2014). This also reveals the sheer amount of maintenance of these tunnels regardless of completion (Boston Globe 2014). In this instance, the old concrete is being replaced to support the higher traffic volume (Boston Globe 2014).

Starting in the early 1980s and progressing into the 90s planning for a much larger undertaking took place (Flint 2015). Because of increasing traffic and increased load on already overloaded elevated highways a new idea, originally pulled from MIT, was put into the planning stages (Flint 2015). At the top of this was three major people, the then Governor Michael Dukakis, Massachusetts Transportation Secretary Fred Salvucci, and US House Speaker Thomas P. O’Neil (Flint 2015). The then Speaker of the House would be the one to secure much of the Federal funding for the project (Flint 2015).

Thomas "Tip" P. O'Neil would get one of the future tunnels named after him.

This plan involved dismantling the “Central Artery” and bringing the highway effectively underground removing an eyesore and also improving traffic in the process (Commonwealth of Massachusetts n.d.). To further improve traffic, an additional tunnel would be created extending I-90 underground and more particularly underwater giving an additional route to the airport (Commonwealth of Massachusetts n.d.). The map above shows the resulting highway system after construction. While some of the projects never took off beyond the planning stages the key infrastructure was built.

“Ours was the mega project of faulty epoxy, light fixtures dropping like pine needles, Ginsu guardrails, and sea water leaks. The boondoggle, good money after bad, the white elephant” (Flint 2015).

Construction would start in 1991 and would continue untill 2007. (LeBlanc 2007). The new highway would be built under the old highway so that traffic could still travel on the old highway during construction (Osgood 2000 CBS News).

Showing the size and scope of this project, the video not only explains the sheer amount of materials required, but also how it definitely effect the people who live near it (Osgood 2000 CBS News). The noise pollution and the dust shot into the air were only two of the side affects of the project (Osgood 2000 CBS News).

Engineers had to use what was known as the “slurry wall method—essentially building one wall of the tunnel and then digging sideways” (Flint 2015). This created problems all along the way especially with most of Boston being build on loose landfill used to expand the city over the centuries (Flint 2015). In comparison to today, construction may have been a bit different. New tunnel drilling techniques and technologies being utilized for the Viaduct replacement for Seattle would have likely saved time and money (Flint 2015). 

As the construction progressed, the costs began to mount and exceeding the budget became a common occurrence during the construction (Osgood 2000 CBS News). However, the need to finish the project was too important for it to be halted especially with a "giant hole in the ground" (Osgood 2000 CBS News).

During the construction, the Big Dig produced mixed opinions among its citizens. Some, such as the people from the beginning of the CBS expose above, were looking forward to it finishing (Osgood 2000 CBS News). This was very true with the cab driver (Osgood 2000 CBS News). But with other citizens and tourists, because it became ingrained so long, people became used to it and even saw it as a landmark of Boston (Osgood 2000 CBS News). Most of my own early childhood was during its construction and I remember it well.

Above describes the positive remarks by Bostonians on the Big Dig construction ranging from an Ice Cream Flavor to popular tours of the construction itself (Osgood 2000 CBS News).

An area near the newly constructed Ted Williams Tunnel, one of the two new tunnels going under the harbor to Logan Airport, went through its own set of issues.

Late at night on July 10, 2006, just only 3 years after the Ted Williams Tunnel opened to the public, a portion of an earlier section known as the D Street Portal's ceiling tiles, which were made of concrete, broke away and fell and crushed a passenger vehicle driving through the tunnel (NTSB 2006). The passenger sadly died and her husband, the driver, escaped the car and survived (NTSB 2006).

This prompted an investigation by the National Transportation Safety Board and suspended use of that highway section including the Ted Williams Tunnel (NTSB 2006).

Upon examination of the accident by the NTSB, it was concluded that the adhesive anchors, that held the tiles in the ceiling had shifted by a great amount leaving it unstable (NTSB 2006). What made it more shocking was that one of the many construction companies that were involved was warned of this by some of its engineers back in 1999 (NTSB 2006). It was however dismissed by the contractor which argued that the cause was not due to the anchors not exceeding their maximum load (NTSB 2006).

It was found that it was faulty epoxy (high strength glue) was the primary cause of the failed anchors (NTSB 2006). It was not designed for the load the tiles exerted and the natural movement of the tiles over time (NTSB 2006). It was also discovered that much of the tunnel's ceiling tiles were on the verge of collapse if not dealt with (NSTB 2006). It found several of the companies at fault: the contractor, the suppliers of the epoxy, and the firm that calculated the type of epoxy required for the load of the tunnel (NSTB 2006). It finally also faulted the Massachusetts Turnpike Authority for failure to start a regular inspection of the tunnel to make sure the anchors would not cause problems in the future (NTSB 2006).

We can of course look back with skepticism and a critical eye but a lot of the benefits that Bostonians and visitors reap would have never existed without this infrastructure project. 

The Rose Kennedy Greenway was one of the side projects of the Big Dig (Flint 2015). With the removal of the highways above, the project set itself on beautifying the area once teeming with concrete and elevated highways (Flint 2015). The project designers wanted a grand landscaping teeming with parks and open buildings (Flint 2015). This however was not possible as the funding was almost gone (Flint 2015). Parks were created though and it worked (Flint 2015). The minimalist look was appealing to Bostonians and particularly developers where the property values in the region skyrocketed (Flint 2015).

Traffic is a difficult topic to reflect on as we reflect on it well over ten years later. A city changes quite a bit in ten years especially with the amount of traffic in the city, and no amount of highway infrastructure can properly handle those changes. The best we can do is observe it critically from the data presented before us.

Shown by the World Traffic Service layer, Boston has a great deal of traffic. The majority of streets and roads are covered in red indicating "stop and go" traffic (ESRI (2) 2019). However, that is quite common for a large city. The important takeaways from this map are the regions upgraded and renovated from the Big Dig. The Central Artery going underground through downtown Boston is clogged with traffic. However, if the tunnel did not exist the elevated highways would have been overloaded way beyond the point they were already in the 80s. Looking at the green arrow on the map, showing the new I-90 route to the airport, traffic varies from medium to high (ESRI (2) 2019). Nonetheless, this route bypasses the gridlock going downtown, and gives people who are not residents of the city an alternate route to the airport. The red arrow, showing the old tunnel route to the airport, ranges as well but shows a clear drop in congestion (ESRI (2) 2019). This allows for drivers coming from I-93S to drive to the airport with low traffic. As a result of the Big Dig, two major routes now exist to the airport from opposite directions entering the city.

A study was conducted by an independent research group for the Massachusetts Turnpike Authority in 2006 for reviewing the economic and overall impacts of the Big Dig post construction (EDRG 2006). It was mainly utilized to show how many more people were passing through the toll booths on Route 1A and I-90 (EDRG 2006). Based on data comparing 94'-95' and 03'-04', travel time decreased slightly with the introduction of the two new tunnels (EDRG 2006). Average Weekday Traffic coined AWDT was the most drastic of changes ranging from a 65% decrease in the Old Callahan Tunnel's usage in morning rush hour (7-8 am) (EDRG 2006). Rush hour in the afternoon (3-4pm) showcased a significant but slightly less 57.5% reduction of the same tunnel route (EDRG 2006).

ABZ Drive. (2019). Boston Massachusetts Tunnels [Video Uploaded to Youtube]. Retrieved on October 10, 2019 from  https://youtube.com/watch?v=KTgYCEQ9z8U  .

Before and after the Big Dig [Reddit Image Post]. (2017). Reddit. Retrieved on October 11, 2019 from  https://www.reddit.com/r/boston/comments/6so8p0/before_and_after_the_big_dig_xpost/ 

BEMH. (2013). Rose Kennedy Greenway—Timelapse [Video Uploaded to Youtube]. Retrieved on October 8, 2019 from  https://youtu.be/kZy0Zmf8MKo  .

Boston Globe. (2014). Callahan Tunnel Construction Progress [Video uploaded to Youtube]. Boston Globe. Retrieved on October 11, 2019 from  https://youtu.be/pcRyYiKwVSY  . 

Commonwealth of Massachusetts. (n.d. otherwise 2019). The Big Dig: Project background. Mass.gov. Retrieved on September 23, 2019 from https://www.mass.gov/info-details/the-big-dig-project-background#introduction- .

Dwyer, Michael [Photographer for Article]. (2006). Accident in Boston’s Big Dig Kills Woman in Car [News Article]. New York Times. Retrieved on October 11, 2019 from  https://www.nytimes.com/2006/07/12/us/12tunnel.html  .

Economic Development Research Group (EDRG). (2006). Transportation Impact of the Massachusetts Turnpike Authority and the Central Artery/Third Harbor Tunnel Project [Research Study PDF]. Retrieved on September 23, 2019 from

https://web.archive.org/web/20110108043647/http://www.massdot.state.ma.us/Highway/downloads/financial/MTA-Economic-V1.pdf . 

ESRI (1). (2019). Topographic Basemap [ARC GIS Online Layer]. Retrieved on September 23, 2019.

ESRI (2). (2019). World Traffic Service [ARC GIS Online Living Atlas of the World Layer]. Retrieved on September 23, 2019, from https://www.arcgis.com/home/item.html?id=ff11eb5b930b4fabba15c47feb130de4 .

Flint, Anthony. (December 29, 2015). 10 Years Later, did the Big Dig deliver? The $15 Billion project is a road paved with failures, successes, and what-ifs [News Article]. Boston Globe. Retrieved on September 23, 2019 from https://www.bostonglobe.com/magazine/2015/12/29/years-later-did-big-dig-deliver/tSb8PIMS4QJUETsMpA7SpI/story.html . 

Heidt, Herb and Eliza McClennen. (n.d.). Map of Boston’s Expansion over the centuries. Original from Norman B. Leventhal Map Center at Boston Public Library, published in National Geographic. Retrieved on October 11, 2019, from  https://www.nationalgeographic.com/news/2017/06/Boston-landfill-maps-history/#close  .

Kelly, Susan Cole [Photographer for article]. (2015). Beacon Hill | New England’s Gifts [Image]. New England Today: Travel. Retrieved on October 11, 2019 from  https://newengland.com/today/travel/massachusetts/beacon-hill/  .

LeBlanc, Steve. (2007). On Dec. 31, It’s Official: Boston’s Big Dig Will Be Done [News Article]. Washington Post. Retrieved on October 11, 2019 from  http://www.washingtonpost.com/wp-dyn/content/article/2007/12/25/AR2007122500600.html?nav=hcmoduletmv  .

NTSB (National Transportation Safety Board). (July 2006). Ceiling Collapse in Interstate 90 Connector Tunnel Boston Massachusetts [NTSB Accident Report PDF]. NTSB: Accident Report PB2007-916203. Retrieved on October 11, 2019 from  https://www.ntsb.gov/investigations/AccidentReports/Reports/HAR0702.pdf  .

Osgood, Charles. (2000). CBS Sunday Morning: Uncovering Boston’s “Big Dig” [News Video uploaded to Youtube]. CBS. Retrieved on September 23, 2019 from https://www.youtube.com/watch?v=eF5aUClwJ9w .