Monday, October 17, 2016

Building The Better Mousetrap: ECI, Signature Bridges, And The Surface Cover That Could Change The Game

The most fundamental question involving construction of the I-49 Lafayette Connector from the beginning has been this: Can a major six-lane freeway be built through the heart of Lafayette that can be integrated with the historic neighborhoods and downtown without wiping them off the map?

Many living in those neighborhoods, along with many advocates for New Urbanism, have said, "Oh HELL TO THE NO!!", citing the history of badly planned and executed freeways being driven through inner cities without any due planning or respect for those being razed. They have been and still are the biggest advocates for swinging I-49 around the city via a bypass, while protecting the inner neighborhoods through "road diets" and reemphasis on non-auto based transportation options.

Thankfully, that attitude is being seriously challenged by a new breed of urban planning that could change the way that urban freeways are built in these areas. And, they just might have more than a snowball's chance in Hell of executing their designs here in Lafayette.

The Evangeline Corridor Initiative (ECI) is an outgrowth of the Evangeline Thruway Redevelopment Team (ETRT), an organization founded by the Lafayette City/Parish Consolidated Government (LCG) as a go-between for redevelopment of the neighborhoods affected by the Connector freeway. The ETRT was formed under the guise of a joint agreement between LCG and the Louisiana Department of Transportation and Development (LADOTD or DOTD) to enact preliminary corridor preservation and property acquisition for the Connector project. It's main focus, however, is to attempt to successfully integrate the Connector project with the surrounding neighborhoods and downtown in a seamless and constructive fashion that promotes both Smart Growth principles and appropriate development.

In 2014, the ETRT applied for and was awarded a $500,000 grant from the US Department of Transportation through its Transportation Investment Generating Economic Recovery (TIGER) Grant program for implementing and integrating the Connector freeway project with the community of Lafayette that would be most impacted by its construction. Their now ongoing study has the goal of not only meshing the freeway with its surroundings, but also provide more direct connectivity between the neighborhoods affected through more diverse options for transport (such as bicycles and walking); as well as improve opportunities for more suitable and better scaled economic development.

To facilitate the implementation of the project, three Areas of Influence were established for the Connector freeway:

-- Area  Level I consisted of the actual right-of-way taken for the freeway facility;

-- Area Level II consisted of a 500 foot buffer zone on either side of the ROW, which would serve as a transition zone between the freeway and its surrounding neighborhoods; and

-- Area Level III consisted of the boundaries of the neighborhoods immediately impacted by the project.

ETRT's and ECI's main purpose would be to develop Area Levels II and III, and interact with DOTD and FHWA on refining Area Level I to meet their goals.

When the ECI originally announced its initial study, the assumption was that the design for the Connector would strictly follow the Selected Alternative that was approved in the 2003 Record of Decision. That alternative consisted of a mostly elevated freeway utilizing most of the Evangeline Thruway corridor, save for a segment near downtown where it would follow a gradual curve just east of the Burlington Northern Santa Fe/Union Pacific (BNSF/UP) main railroad line. Two standalone interchanges along that section with a realigned Second Street/Third Street couplet and Johnston Street would provide direct access to downtown and the neighborhoods surrounding that area; grade separated underpasses of the railroad line would prevent conflicts. Other than a brief section between Jefferson Street and Johnston Street where the mainline freeway would be elevated on embankment to account for the ramps to the two close interchanges, the mainline would be elevated for most of its entirity. Higher than usual vertical clearances (22 feet rather than the typical 16.5 feet) would be used in the segment between the Louisiana and Delta Railroad (L&DRR) spur line and Simcoe Street as part of mitigation for the visual impact to the Sterling Grove Historic District neighborhood. Also, the existing Evangeline Thruway couplet would be retained as part of a frontage road system feeding the Connector freeway and providing secondary access along with the interchanges.

Aerial profile of I-49 Lafayette Connector Selected Alternative, based on
2003 Record of Decision and 2007 Conceptual Study

However, when the Conceptual Study was revived in October of 2015, those assumptions quickly were rendered useless. There was the historical strong opposition from those who opposed building the freeway through Lafayette from the very beginning, preferring a bypass alignment to the east such as the Teche Ridge Bypass or the Lafayette Regional eXpressway (LRX) alternative to the west.

However, a different form of opposition soon emerged from downtown interests who did favor the central alignment, but begged to seriously differ on some of its details. The Lafayette Downtown Development Authority (LDDA) was particularly not so keen to some elements of the Selected Alternative; and their objections were reinforced through both the public involvement process of the main Conceptual Design Study and the initial meetings of the Evangeline Corridor Initiative through their innovative "charrette" meetings. The main objections were:

1) The two standalone interchanges with the Connector at Johnston Street and Second/Third Streets took way too much right-of-way that could be used for development, and were unnecessarily divisive for connectivity.

2) The embanked segment of the mainline between Johnston Street and the Jefferson Street underpass was too divisive, and severed an important collector (Sixth Street/Lee Avenue).

3) The Second/Third Street couplet interchange/railroad underpass potentially forced too much traffic onto Congress Street (which the couplet directly fed into), which contradicted plans for remodeling the latter as a "Complete Streets" prototype for pedestrian/bicycle access and slowing vehicle speeds. It also potentially impacted the Coburn Building, an old retail shop that had recently been approved into the National Register of Historic Buildings.

In reaction to those objections, LADOTD was induced to add a six-month period where modifications to the Selected Alternative could be proposed to address these needs. While the alignment remained the same as to not disturb the concept approved by the 2003 ROD, tweaks to the system of access were proposed, ultimately resulting in 19 design "refinement" modifications by May of 2016.

The ECI study was conceived to run parallel with and advise the DOTD study, and to provide some form of feedback for addressing the Joint Use and greenspace requirements for the freeway. Originally, the idea was that ECI would serve only to perform the development of design for Levels II and III...but as the ideas kept rolling in, it was becoming apparent that they should intervene with DOTD to offer up their own alternative designs more suitable to their goals. In the end they settled on two main concepts, both based on concepts developed by DOTD, but with their own alterations.

Elevated Mainline with Signature Bridge

Overview of Elevated Mainline with Signature Bridge
concept from Evangeline Corridor Initiative
(from ECI Draft Charette Report)
DOTD Concept 4D (Evangeline Parkway), the genesis of ECI's
Elevated Mainline with Signature Bridge design

Generally based on the Series 4 concept from DOTD, this alternative design entailed a continuous elevated structure along the length of I-49 from the Chalmette Drive crossover all the way to the Vermilion River crossing (or even the University Avenue/Surrey Street crossing). The effect would be more of a large scale land bridge crossing Lafayette, with the peak of the crossing designed as a "signature bridge" landmark that would define downtown Lafayette. Instead of direct interchanges downtown, access would be provided through direct connection "slip ramps" to a redefined Evangeline Thruway frontage system, with the slip ramps placed between the L&DRR and Mudd Avenue for north access, and between Pinhook Road and the Vermilion River crossing for south access. The Evangeline Thruway southbound roadway would be reformed as a six-lane urban boulevard for local business development; the northbound Thruway roadway would be downgraded to a two-way local street and returned to the local grid for the McComb-Veazey neighborhood. Accessibility and connectivity would be improved and restored underneath the "signature bridge" by adding additional cross streets over the BNSF/UP railroad, and restoring some one-way streets to two-way for refining the downtown grid. The space immediately under the bridge structure would be developed for public parking and green park space.

Semi-Depressed Mainline with Cover (Surface Tunnel)

This concept was actually not included in the 19 design modifications put out by DOTD, but is a modification by ECI of one that was included. Part of the Series 6 concepts, this was originally developed thanks to input from an unnamed constituent who noted that an original concept of a depressed Connector freeway was vetted and rejected in the early studies. That concept would have depressed the mainline freeway 20 feet below ground level within the median of the the entirity of the Evangeline Thruway. While it was ruled to be marginally feasible, it was rejected out of practicality and the need for I-49 as a hurricane evacuation route. The constituent suggested that maybe a partially depressed freeway would work better; and studies did confirm initially that a 10 foot drop would better allow for gravity drainage.

The Series 6 concept designs are based on dropping the elevated segments from just south of the L&DRR spur overpass to Pinhook Road down 10 feet below ground level, and adding 10 feet of vertical clearance, for a total of 20 feet. Crossing streets would then be allowed to pass over the freeway for connectivity. The first concept (6A) called for an open trench; subsequent concepts added the cover for a partially submerged tunnel effect.

The ECI Covered Semi-Depressed Mainline alternative is an adjustment to LADOTD's Concept 6E, which originally called for flattening the curve of the mainline freeway and also shifting the alignment of the BNSF/UP rail line 150 feet east of its current ROW and dropping it to the same level as the freeway. All ECI did was to return the rail line back to its current trajectory, but keep the shift of the freeway centerline so that the resulting berming over the freeway tunnel could return to existing grade prior to the rail line. This allowed all the crossing streets to retain at-grade crossings of the railroad, removing the need for overpasses.

The other striking feature of the Semi-Depressed/Covered Mainline alternative is that the Evangeline Thruway is essentially replaced altogether with an avenue/boulevard hybrid built directly on top of the tunneled mainline segment, and accessible through the same "slip ramp" connection system as the Elevated Mainline uses. The original Thruway roadways would be downgraded to local streets within the neighborhood grid. (There is an option that utilizes both the avenue on top and the boulevard on the side.)

Initially, DOTD balked at including ECI's alterations to their Series 6 options in their initial analysis, citing both the protocol of DOTD handling Area Level I and that the time for entering concept modifications had passed. Under strong pressure from LCG officials insisting that the alterations be added (as a new concept "6F"), DOTD partially relented and allowed for consideration of the ECI alterations to 6E, provided that that series passed the initial Tier I analysis...which it did by August 2016. All of the modifications under Series 4 and 6 are now currently under a more involved Tier II analysis by DOTD, which will result in the culling down to three finalist alternatives by the end of October, and a final selected and approved alternative by the end of December.

Reinventing Lafayette Gateway North...The Arc d'Willow???

Another goal of the ECI study was to find new ways of exploiting the Connector freeway to redevelop neighborhoods that had been struggling to rise economically. The Lafayette North Gateway District is one distinct example. Once a center of activity through Northgate Mall, Albertsons', and Walmart, North Lafayette along the Evangeline Thruway has suffered greatly economically, and it is accelerated by the lack of through access due to the nature of the at-grade Thruway.

The original concept for the Selected Alternative in this area was to integrate the Evangeline Thruway into the frontage road system as traditional one-way frontage roads, with a slip-ramp diamond interchange at Willow Street and underpass connections at Martin Luther King Drive/Castille Avenue and at Donlon Avenue/Walmart Drive. The Gateway Visitors Center within the median of the Thruway would be removed and relocated to make room for the Willow Street overpass/interchange.

Needless to say, the ECI folks took one look at those plans and announced: "Ummmm...nope. We can do much better than this." And this was the result:

The second most distinct feature of this refinement is the radical transformation of the Willow Street interchange. No more slip ramp diamond; now it's a huge circle interchange with the ramps from I-49 connecting directly to the circle rather than the frontage roads. The MLK/Castille and Donlon/Walmart intersections are now smaller circle/roundabouts, too, and all connected with two-way local streets fronting houses and mixed-used development. Both the Northgate Mall and Walmart properties are also transformed into mixed-use/smaller business development as well.

I did say second most distinct, right? For #1, you got to look what's inside the Willow Street Circle. Behold, behold...the Arc d' Lafayette!!

Yes, that would be a 60 foot imitation of Paris' Arc d'Triomphe straddling the Connector overpass of Willow Circle, complete with a new home for the Visitors' Center and an observation deck on top. This is what you call "thinking outside the box".

All of this may seem quite expensive and beyond the reach of funding for the Connector freeway, but considering the alternative of not completing I-49 South or having it diverted around Cypress Swamp and St. Martinville and Breaux Bridge for no benefit, I'd say that this deserves more than just a look.

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