Finally, A Fresh Connector Update: Tier III Studies Now Underway; LFT Airport Runway Issues Resolved; New Design For University/Surrey & Kaliste Saloom Interchanges, And More

Well..after three months of what seemed to be inaction, the I-49 Connector Concept Refinement Process/Supplemental Environmental Impact Statement/CSS Design processes seem to be back in action now.

On Wednesday and Thursday, two of the Connector CSS Committees – Community Work Group on Wednesday and Technical Advisory Committee on Thursday – had their first meetings in three months to get an update from the Lafayette Connector Partners consultant team on progress with the project. In case you have missed it, the LCP team recently got their contract extended for another 2-1/2 years in order to complete the Supplemental EIS and produce a new revised alternative to the freeway design approved in 2003.

The main points that came across from the meetings can be summarized below.

First, some major design tweaking was finalized on the southern section near Lafayette Regional Airport, in response to some major issues that had to be resolved.

The original concept passed by the 2003 ROD assumed that one of the LFT runways (Runway 11-29) would have to be displaced by 350 feet to allow for a regulation design for the University Avenue/Surrey Street overpass of the Connector mainline to avoid violating that runway’s flight path. In October of last year, however, the Federal Aviation Administration (FAA) imposed new rules requiring airports to install Emergency Materials Arrestor Systems (EMAS) runway extensions to prevent overruns of aircraft; this would have potentially added an additional 300 feet of runway extension to the already planned 350 feet displacement that would have been required for the Connector freeway.

Given that such an addition would have required taking far more wetlands than would have been proposed, the FHWA and the LCP was forced to reassess the design for the University/Surrey interchange and develop alternatives that would not require the runway displacement. This is required because Section 404 regulations are pretty tough on displacing wetlands.

The alternatives discussed included:

— Lowering the profile of the Connector freeway overpass over University/Surrey so that the existing flight path (without the 350′ runway displacement) would be retained. This would be accompanied by lowering the grade of University/Surrey to allow standard vertical clearance below the underpass.

— Shifting the design of the University/Surrey interchange so that University/Surrey would pass over the Connector freeway on a partially elevated structure, while the Connector mainline would be partially depressed to cross underneath University/Surrey.

— Shifting the alignment of University/Surrey sightly to the north to move the interchange further away from the glide path of Runway 11-29. This would, however, come with some major issues of taking land from Beaver Park, which is a Section 4(f) property, and potentially taking access from a boat launching facility for Beaver Lake, which would be a potential Section 6(f) violation. Both 4(f) and 6(f) regulations require that alternatives be taken to prevent taking of protected resources.

Ultimately, it was decided that the best and most cost efficient course was Option #1: reduce the profile of the Connector overpass and lower University/Surrey. This effectively removes the risk to Runway 11-29’s glide path and allows for the EMAS extensions to be implemented.

Another significant change was the revision of the design for the proposed Kaliste Saloom Road interchange. The original design approved by the 2003 ROD called for a 3-way fully directional interchange with flyover ramps over the Connector mainline and BNSF/UP railroad mainline. The highest ramp (from northbound Kaliste Saloom to the northbound frontage road and northbound Connector mainline) would be up to 40 feet high. Here’s an illustration graphic of the original proposal (from the presentation given at the latest meetings, via the Lafayette Connector website):

Also notice how the original design had the southbound frontage road wrap around the back of the Acadiana Dodge car dealership, and how the original ramps and access road connecting Kaliste Saloom Road and Hugh Wallis Road conflict with a hotel establishment that was recently built.

In its place, the LCP design team created an interesting alternative design which reduced both the ROW required and the height of the interchange. The flyover ramps are replaced by a single structure where the left turning movements (from east bound Kaliste Saloom Road to northbound Evangeline Thruway/I-49 and from northbound I-49 frontage road to westbound Kaliste Saloom) meet and cross each other at grade, similar to a Single Point interchange. In addition, the connecting access road between Kaliste Saloom and Hugh Wallis is shifted south to parallel the new Kaliste Saloom overpass structure, and split into two roadways which connect to Kaliste Saloom Rd. via RIRO (Right-In-Right-Out) connections just east of the Episcopal School of Acadiana entrance.

The new design also shifts the southbound frontage road to flank the Connector mainline, passing in front of Acadiana Dodge rather than behind it. There was some concern that such a design would require taking the showroom of the dealership, but apparently that has been resolved.

In addition to these changes, the LCP team also addressed which Potential Design Modifications (PDMs) would advance into the Tier III process. The page below lists all the PDMs considered. The ones highlighted in black are the ones that advanced into Tier III and will be incorporated into the End-to-End Alternatives to be studied in the SEIS; the red highlighted ones are those that were totally rejected; and the blue highlighted ones were to be further negotiated and discussed.

The most striking aspect about this list is that the blue highlighted PDMs that remain to be resolved all have to do with enhancements desired by Lafayette Consolidated Government to mitigate the impact of the Connector through the central core of Lafayette, but which by law the Federal and state government couldn’t fund directly as part of the project. This means that if LCG wants to have a signature bridge or pedestrian walkways or a higher clearance for the elevated structures, they would have to find the revenue to pay for it. That may be a significant sticking point, considering the paucity of funding and the general attitude against taxation.

Another real sticking point comes around the rejection of PDM #23-7, a proposed “dogbone roundabout” design for the Willow Street interchange.  The Evangeline Corridor Initiative, a project of the Evangeline Thruway Redevelopment Team that was paid for by a Federal TIGER Grant, had proposed a different interchange design for Willow: a large rotary circle interchange in which an arch-like structure would straddle the elevated mainline to serve as a gateway for North Lafayette.

The LCP design team, though, had blown off the ECI’s proposal in favor of studying the “dogbone roundabout” design, which they have developed and implemented in other areas. Their traffic studies found that such a design would not work for Willow Street due to heavy turning volumes between Willow Street and the Evangeline Thruway/Connector, and pretty much recommended the original “slip ramp” diamond interchange design approved by the 2003 ROD.

Obviously, representatives of the ECI were not too happy, as seen in this snippage of coverage of the meetings from the Lafayette Advertiser:

Kevin Blanchard, who sits on the Evangeline Thruway Redevelopment Team working for the city to improve the Evangeline Thruway area in conjunction with the I-49 project, was surprised to learn the ETRT’s plan for a rotary circle with signature feature at Willow Street has been scrapped by the I-49 planners.

The I-49 Connector will be elevated as it crosses Willow Street, a gateway into the city. Blanchard said the ETRT team proposed a large rotary circle with a gateway feature such as an arch that would add value to the urban space.

Blanchard asked for a comparison of traffic volumes expected in a roundabout versus a rotary circle.

“We’re talked in this process about partnering with locals,” he said. “Let’s look at what was proposed locally, which was not a roundabout. It is one of the priorities of the ETRT.”

This isn’t the first time that the ETRT has clashed directly with the Connector planners; it took the ECI to force the LCP and LADOTD to even consider the Partially Depressed/Cut and Cover options for Tier II, only to have it removed from further consideration with great consternation in Feburary.

The next steps for the LCP will be to finalize and introduce to the public the End-to-End Alternatives, that will then be refined and reduced to two finalist Supplemental Alternatives, which will then be fully vetted through the Supplemental EIS process. The original 2003 EIS/ROD Selected Alternative will also be included, but only as a control for comparison to the others. It’s assumed that a Supplemental Preferred Alternative would be presented prior to the release of the Draft SEIS, probably by spring of next year, with a Final SEIS/Supplemental ROD approved by fall of 2018, and the remainder of the Corridor Functional Plan process involving finalization of the CSS design elements finished by October of 2019.

Unless, of course, the Sierra Club and Citizens for Good Government decide to intervene with their inevitable lawsuit challenging the SEIS/SROD for threatening the Chicot Aquifer and pushing for their favored Teche Ridge Bypass.

As always, I’ll break in this space here with any further developments.

I-49 Lafayette Connector Update: Tier II Analysis Nearly Completed, ECI Surface Tunnel Gets Stoned, Elevated Option Most Likely Solution

[NOTE: All illustrations are from the Tier II Draft Technical Memo Findings Report that was introduced to the three I-49 Connector committees on November 4th and 5th; and were posted to the LADOTD Lafayette Connector website on November 5th. The report is downloadable from that website as part of a compressed folder in the “Project Library” section under any one of the relevant committee bar tags.]

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This week was a long awaited week of movement in plans towards the Lafayette Connector freeway project. The Connector Design Team , under the leadership of the Louisiana Department of Transportation and Development (LADOTD) and the Federal Highway Administration (FHWA), unveiled yesterday the notes and results of their Tier II Analysis of the 2 remaining design concepts for the central core portion of the project; and the report opened and closed many options.

In case you may have missed it: LADOTD had decided after their initial Tier I Concept Analysis back in August to further study 2 conceptual designs for the central core: an elevated freeway mainline with cross streets passing underneath and the Evangeline Thruway used as dispersion between the freeway and downtown; and a partially depressed mainline (10 feet below ground level + 10′ above for 20′ of vertical clearance) with cross streets passing over the freeway. The latter option was itself divided into two sub-concepts: an open trench with cross-street bridging, and a “surface tunnel” or “cut and cover” option where the freeway would be capped and covered with embankment allowing the cross streets to pass over the tunnel. The “surface tunnel” variation was in direct response to feedback from the Evangeline Thruway Redevelopment Team’s Evangeline Corridor Initiative (the program to reconnect neighborhoods affected by the Connector that was partially funded by a federal TIGER grant) and some in the public who wanted what they thought would be a less visually impacting corridor.

The final draft of their Tier II analysis just came in….and it doesn’t look too good, unfortunately, for the “surface tunnel” option. Based on the initial scoring and the costs, it looks more and more like the Elevated option, probably with a conversion of the existing Evangeline Thruway core section to a “grand boulevard”, will become the chosen alternative for the Connector freeway.

Before we get to the meat of the analysis, a quick review of the background.

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FEIS/ROD Selected Alternative/Concept 1A & ECI Alterations

The original Selected Alternative based on the 2003 Final Environmental Impact Statement/Record of Decision is illustrated below.

Original Refinement Concept 1A, consisting of the
Selected Alternative approved through the
2003 Final EIS/Record of Decision

That concept included standalone interchanges with Johnston Street and a consolidated couplet of Second and Third Streets, a mostly elevated mainline on structure (except for a section on fill between Jefferson and Johnston Streets, railroad grade separations with the above mentioned interchange locations (along with the current Jefferson Street underpass), and maintaining the existing Evangeline Thruway one-way couplet as part of the frontage road system.

Most local officials immediately panned this alternative because, according to them, the interchanges and underpasses took up too much space that could be more useful for economic development, the filled embankment section and interchange ramps were too divisive and didn’t allow enough connectivity, and the interchanges brought too much traffic into streets that they were trying to downgrade for “Complete Streets” multimodal use (bicycles and pedestrians).

The Connector Design Team responded by opening up the process to allow for “refinements” to the design for the core segment; this produced a total of 19 concept refinement proposals utilizing 6 concepts. It was here that the ETRT and ECI attempted to intervene with their ideas for better neighborhood connectivity and compatibility with “New Urbanism” techniques of broadening mixed use development. In early August, DOTD announced that they would reduce the level of alternative concepts for their Tier 2 series of detailed analysis down to two: the Elevated Mainline (Series 4) and the Semi-Depressed Mainline (Series 6). This was also in sync with the ECI pushing out their own proposed concepts based on those two alternatives. For posterity’s sake, here are the two ECI options for the downtown core of Lafayette. (From the ECI’s September 27th Charrette Report)

The hope for the ECI was that initial testing did show their Partially Depressed and Covered Mainline to be marginally feasible, and the possibility of huge economic development gains from exploiting the space over the freeway would justify the higher costs as compared to the Elevated Mainline option.

Unfortunately, it appears that those hopes have been dashed to pieces upon further analysis by DOTD engineers.

For the last 2 months, DOTD and the Connector Design Team basically reworked and tested the Elevated, Partially Depressed/Open Trench and Cut-and-Cover designs, eventually resulting in 4 final proposed design options that were presented this week. Let’s go through each one individually:

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1) Concept 4-1: Elevated Mainline with Evangeline Thruway Couplet

There are some aspects where the Design Team did incorporate some elements desired by the ECI “TIGER Team”; they “flattened” the mainline in the area between Second Street and Taft Street so that it paralleled Chestnut Street and the Burlington Northern Santa Fe Railway (BNSF RR) line; and they did do away with the original plan of a loop ramp at Taft Street for connecting the Thruway to the southbound Connector mainline in favor of a more traditional slip ramp pair to the Thruway at Eleventh Street. In addition, the Elevated Mainline would assume a taller structure for the viaduct; only thing left to be determined would be whether a 22′ or 30′ vertical clearance would be utilized.

In Concept 4-1, the Evangeline Thruway stays mostly in its existing one-way couplet up to just past Jefferson Boulevard, where it transitions into boulevard-like facility centered on the southbound Thruway roadway, to get away from the Sterling Grove Historical District and the St. Genivieve Catholic Church. It then gets incorporated into the freeway frontage road system, but with the northbound Thruway roadway rebuilt on new alignment parallel to the mainline; the former northbound roadway would be transformed into a local two-way street (Cigg Street before the Thruway was built, maybe??)

Cross section profile for Elevated Mainline

The existing profile for the Elevated concepts allows for a 22 foot vertical clearance under the structure in order to reduce the visual impact to surrounding areas; however, there is an option to even further increase the height to allow for a 30′ clearance, which could possibly raise the height of the freeway to as much as 45′ above ground level.

I-49 Connector Elevated Profile Heights above current
ground level, reflecting both 22 foot & 30 foot verticals
Another interesting adjustment is that Simcoe Street is essentially severed across the freeway mainline in order to free up more space for mitigating the visual impact on the St. Genevieve Church property. On the west side, Simcoe traffic would be diverted to Chestnut Street and then the Second/Third one-way couplet, which would then tie back into Simcoe on the east side. There would be also a new connection on the west side using the old Dudley Avenue right-of-way to connect with Greig Street. (Dudley Ave. was absorbed by the southbound Thruway when the latter was built.)
Section of I-49 Connector Elevated Option near Sterling Grove
Historical District (Concept 4-1, with One-Way Couplet)
Also noted is that Mudd Avenue, which traverses the Sterling Grove District, is severed between the former northbound roadway/future local street and the rebuilt northbound Thruway frontage road. This is apparently to remove direct heavy traffic access from Mudd eastbound, and to further provide a continuous buffer for homes in Sterling Grove and the St. Genevieve church/school property. Mudd would still have full access to the Thruway frontage system, though, because it would pass underneath the freeway mainline to connect with the northbound roadway. 
Treatment of Mudd Avenue intersecton with
realigned Evangeline Thruway frontage system
under both Elevated concepts (severage between
new northbound Thruway and former northbound
Thruway roadway converted to local street)
The proposals from the Evangeline Corridor Initiative studying means to retain connectivity throughout the Connector freeway corridor originally recommended Mudd Avenue be retained as a continuous arterial across the freeway/frontage system, but with the portion crossing the Sterling Grove Historical District converted into a “Complete Streets” multimodal facility more friendly to bicycle and pedestrian traffic. Both Concept 4 plans differ in that they would sever Mudd between the new northbound frontage road and the former northbound Thruway roadway, which would be converted back to a local two-way street. Negotiations with Sterling Grove residents and further feedback could get that connection restored during the latter stages of Tier III analysis.
Essentially, this is Concept 4A from the Tier 1 studies, with some minor tweaking. Other than the changes around Sterling Grove and St. Genevieve, and the addition of the elevated portion shadowing Chestnut Street, it’s pretty much status quo.

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2) Concept 4-2:  Elevated Mainline with Evangeline “Grand Boulevard”

This concept is basically the same as 4-1 but with one important exception: the Evangeline Thruway one-way couplet is replaced with a tighter “urban boulevard” taking up the southbound roadway’s ROW and just to its west. The northbound Thruway in its entirity is downgraded to a two-way local street. (Clay & Magnolia Streets used this ROW before they were taken by the Thruway.) The complimentary Tier 1 proposed refinement concept was Concept 4D.

Original Refinement Concept 4D, which served as the
genesis for Concept 4-2

The freeway would be pretty much offset by one block in the downtown core area from the Thruway frontage system (whether a couplet or a boulevard); and, as I said, Chestnut Street would remain open but would be shadowed by the open freeway structure. Full access underneath the freeway would be retained. The same option for higher vertical clearance (30′ instead of 22′) would exist for Concept 4-2 as it would for 4-1, as would the same revisions for access for Sterling Grove.

Section of I-49 Connector Elevated Option near Sterling Grove
Historical District (Concept 4-2, with Boulevard)


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3) Concept 6-1: Semi-Depressed Mainline with Open Trench

This proposal is an improvement on Concept 6A in the Tier 1 study, with refinements and adjustments developed through feedback with the Evangeline Corridor Initiative group. Its main feature consists of dropping the Connector freeway mainline 10 to 12 feet below ground level, while also allowing an additional 10-12′ of vertical clearance space above ground level. This would meet the DOTD standards for 20′ of vertical space for freeway vehicles. Important cross streets would be elevated over the freeway via bridge structures.

Original Refinement Concept 6A (Semi-Depressed with
Open Trench); the genesis for Tier 2 Option 6-1

One interesting variation that was added since Tier 1 was the realignment of the southbound Evangeline Thruway roadway south of Johnston Street to pass over the mainline before Taft Street in order to align itself correctly with the southbound frontage road near Pinhook Road. This realignment requires a similar realignment of Taft Street to pass over the freeway, shifting its connection with the northbound Thruway roadway from Fourteenth Street to Thirteenth Street. Also, Fifteenth and Sixteenth Street would be severed at the Thruway to allow for the south connection ramps to slope properly.

Profile of Semi-Depressed Open Trench structure

The same evolution of the Thruway into a semi-boulevard from Jefferson to Simcoe, then to a parallel frontage road system north of there, would exist as with the Elevated option. However, the access for the Sterling Grove and Ballard Addition neighborhoods would be radically different with the Partially Depressed option due to the needed transition of the mainline from depressed to elevated to cross the Louisiana & Delta Railroad (L&D RR) spur line. Mudd Avenue would have to be completely severed across the freeway, and would be connected only with the frontage roads with no access between them. Chestnut Street would be totally wiped out, of course; so access for Simcoe would have to be switched to North Grant Street to access Second Street to cross the freeway and get to the east side. (Second and Third Streets would become autonomous two-way streets rather than a one-way couplet in this option.) Simcoe on its eastern flank would be diverted into the Dudley Avenue ROW and then turned back onto Greig Street with no connection at all to the southbound frontage road. Bellot and Tissington Streets would be the only means of cross-street access north of Second Street for Sterling Grove and Ballard Addition up to the L&D RR crossing.

Closeup view of cross-street access changes near
Sterling Grove Historic District from
Concept 6-1 (Semi-Depressed Open Trench)

But the rubber starts to really hit the road with the Semi-Depressed option (and Cut-and-Cover option as well….more on that later) with the downtown major cross street crossings and how they cross the BNSF railroad. The original Concept 6A proposal had Jefferson, Sixth, and Johnston Streets all grade separated over both the freeway and the rail line. That created some issues with the cross street railroad bridges extending past Cypress Street on the west side and disabling it as an access street; as well as issues with Johnston Street’s intersection with Cypress Street and Garfield Street, which sets the boundary for the Freetown-Port Rico neighborhood. That’s a major issue, considering that F-PR was recently made an Historical District with all the protections included.

Original concept for Tier I Enhancement Option 6A
(Semi-Depressed Mainline) showing grade-separated
overpasses of BNSF RR at Jefferson, Third, &
Johnston streets

The original 6A, as seen in the above graphic, used the original curvature of the 2003 ROD Selected Alternative, bringing the freeway close to the BNSF rail line near Johnston Street. The ECI folks, in their Charrette presentations, proposed the idea that if the curvature of the freeway mainline was “flattened” to push the apex of freeway curvature 150 feet eastbound away from the railroad, there would be enough space that the cross streets would return to ground level to cross the rail line at grade. The general idea for the ECI proposal was to have 50-100 feet of slope on either side of a 150′ mainline ROW, raised 18′ above ground level, and returning to existing level before the rail line to the west and the existing southbound Evangeline Thruway to the east. (More on why that idea fell apart for the Surface Tunnel option later on.) The original ECI Covered Mainline proposal for the downtown segment is illustrated below:

Evangeline Corridor Initiative’s original concept
for Semi-Depressed/Cut-and-Cover “Surface Tunnel”;
including “flattening the curve” of mainline
& shifting Evangeline Thruway frontage roads
to directly above/flanking covered freeway (from 10-27-16
Charrette Report)

DOTD and the Design Team, upon further study, found and reported that the concept of returning the cross streets to existing grade at the BNSF RR crossings would marginally work with the crossings at Second, Third, Jefferson, and Sixth streets. While those roadways could be returned to ground level in time to cross the BNSF/UP railroad at grade, there would be some issues with the slope of grade (nearly 7%) approaching the railroad crossings, especially for high profile vehicles. It was, though, technically feasible. Note that this option replaces the existing Jefferson Street underpass of the BNSF rail line with an at-grade crossing….for obvious reasons.

Overview of proposed Semi-Depressed overpasses of
Second, Third, Jefferson, and Sixth streets; with return
to level-grade BNSF RR crossings
Profile of Semi-Depressed option overpass of Third Street
(would also apply to Second, Jefferson, and Sixth)
Semi-Depressed (Open Trench)
cross street gradient profiles for
Downtown section
Such was not the case, unfortunately, for the Johnston Street crossing. The studies found that there simply wasn’t enough space between the depressed freeway ROW and the railroad to allow for a safe return to grade to provide a grade level crossing. 
Original profile of Johnston Street overpass of Semi-Depressed
option returning to level grade to cross BNSF RR (rejected
due to insufficient space)

Thusly, the only alternative for Johnston Street was to elevate it in order to cross over the railroad. And that’s where everything starts to fall apart. For starters, the required 23.5′ clearance over the BNSF rail line would be much higher than the clearance needed over the Semi-Depressed freeway ROW. Most important, though, is that the overpass would require an excessively steep gradient to the west of the railroad if the idea was to return Johnston to grade near the Cypress Street/Garfield Street intersection. That was important because Johnston runs right through the Freetown-Port Rico neighborhood, which was recently endowed with Historical District status, giving it special protection against any intrusion upon it. Johnston Street is also the main arterial to the campus of University of Louisiana at Lafayette, and ultimately serves as the hurricane evacuation route for Vermilion Parish. You really don’t want hurricane evacuation traffic having to traverse a 9% grade.

Original Johnston St. BNSF RR overpass profile with Semi-
Depressed option to avoid penetrating Freetown-Port Rico
Historic Distric
t

An alternative that was proposed to mitigate that situation was to raise Johnston Street and extend the structure to meet level grade at Vermilion Street to produce an acceptable gradient of 4%. That would not only require elevating the Garfield Street intersection nearly 12′ above ground and severing Cypress Street; but also elevating Lincoln Street’s intersection as well. The resulting penetration using Johnston Street would be a serious encroachment of the Freetown-Port Rico Historical District, bringing the full wrath of Section 4(f) and Section 106 violations. Nevertheless, the proposal here does include the elevated and separated Johnston Street overpass with the extended gradient.

Johnston St. profile for Semi-Depressed option
revised for sufficient gradient profile; note serious penetration
of FTPRHD due to need to elevate Garfield & Lincoln
streets.

Vertical view of intrusion of revised Johnston
St./BNSF RR overpass for Semi-Depressed
Open Trench option into Freetown-Port Rico
Historic District

You can notice also how the intersection of Johnston Street and the southbound Evangeline Thruway/frontage road has to be elevated on fill to meet the profile of the railroad overpass.

The Semi-Depressed alternative would also have some very severe ramifications for the neighborhoods surrounding the Sterling Grove Historical District as well. While the SGHD would not be impacted directly with any ROW takings with this or any other of the proposed concepts (same with the original 2003 ROD Selected Alternative), there would be some very nasty indirect impacts.

For starters, the Evangeline Thruway between the L&D RR rail spur crossing and Jefferson Street would have to be totally rebuilt and raised on either fill or structure to adapt to the standard vertical clearances required for the 10′ depressed mainline. This would mean the Thruway and cross streets would have to be raised as much as 8 to 10 feet, and the actual crossing of the mainline would require as much as a 19 foot vertical clearance. While the northbound Thruway roadway would be shifted westward further away from the SGHD (and especially Saint Genevieve Catholic Church and School, which directly fronts the original northbound Thruway roadway), the raised height would still introduce at least a strong visual impact.

Semi-Depressed Open Trench cross street
access changes for Sterling Grove/Simcoe/
Second/Third/Jefferson area
Roadway vertical profile heights for Semi-Depressed
Open Trench option (values are above ground level)
Profile gradients of cross streets & frontage system for
Semi-Depressed Open Trench option
Then, there is the severing of Mudd Avenue at its intersection with the Thruway frontage roads. Due to the need to elevate the southbound roadway to cross over the mainline, Mudd on the west side is “teed” (terminated at a T intersection) at the southbound Thruway, while its east side going through the SGHD is similarly “teed” with the realigned northbound Thruway frontage road. No access across the freeway is possible there due to the vertical clearance requirements for the mainline. Considering that Mudd Avenue is an important arterial that also carries US 90 off of the Thruway, that’s an important issue. 

Severage of Mudd Avenue due to Semi-Depressed Open Trench
option

The local cross streets from Goldman to Tissington up to the rail spur are kept open underneath the mainline (where it transitions to an elevated facility to cross the rail spur) to allow for cross access. The elevation of so many cross streets would require far more displacements and loss of access for residents, causing much more disruption for those neighborhoods.

The same would also go for the segment near Taft/Fourteenth streets, because of the realignment of Taft Street to connect with Thirteenth rather than Fourteenth, and the subsequent severing of Fourteenth, Fifteenth, and Sixteenth streets to accomodate the south connection ramps and the raised grades for the southbound roadway to pass over the mainline and connect with Taft.

Treatment of cross street access with
Semi-Depressed Open Trench option
near Taft St./Pinhook Rd. area

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4) Concept 6-2: Semi-Depressed “Cut-and-Cover” Mainline

This concept originally evolved out of Concept 6E of the earlier Design Team Concept Refinements. The original thought was that perhaps if both the railroad and the freeway mainline were shifted east a bit, the overpasses would remove the impact of at-grade rail crossings. One look at the implications of derailments of the railroad within the tunnel, as well as the impacts to access downtown, was enough to render that concept as impractical.

Original Refinement Concept 6E, which served as the foundation
for both the ECI Semi-Depressed Covered Mainline proposal
and the ultimate Tier II Concept 6-2 “Cut-and-Cover” option

However…..the Evangeline Corridor Initiative group (aka the “TIGER Team” due to the Department of Transportation grant it was bestowed upon to study integrating the Connector freeway into the community better) seized upon the burnt ashes of Concept 6E to develop their own alternative which they though could serve the same goals better. The resulting “Surface Tunnel” proposal eliminated the overpasses altogether and pushed the railroad centerline back to its existing ROW, creating enough space between the freeway ROW and the railroad to allow all the cross streets to return to grade.

Evangeline Corridor Initiative’s “Partially Depressed
and Covered Mainline” proposal

It certainly looked more than good on graphics, and it was enough for LADOTD to allow that concept to get more detailed vetting in the Tier II process. Unfortunately, the same problems and issues that affect the Semi-Depressed open trench also dissuade the Cut-and-Cover option as well…and then some.

It should be noted that the ECI propsal extended the capped/tunneled section north to include a total reconnection of Mudd Avenue, and allowed for the extension of some more local streets between Johnston and Taft streets for better connectivity. Apparently, DOTD found those to be impractical, because they don’t make their final Cut-and-Cover proposal. The cap remains set between Second Street and Taft Street, with the remainder of the mainline open-trenched.

Profile of Cut-and-Cover Tunnel structure

The same issues involving the downtown cross-street crossings with the Semi-Depressed open trench also exist with the Cut-and-Cover tunnel…but with the additional need of even higher vertical clearances to accommodate the cap. The result for the minor cross streets (Second, Third, Jefferson, Sixth, and Taft) is an even steeper gradient required to return the streets to grade to cross the BNSF/UP line. Even with that, the gradients are still marginally feasible (although, according to LADOTD, “not desirable”). Note also that, as with the Semi-Depressed open trench, the existing Jefferson Street underpass of the BNSF RR is removed and replaced with an at-grade crossing.

Downtown cross street gradients for
Cut-and-Cover option

Vertical profile for Cut-and-Cover Third St. Overpass
(applicable to Second, Jefferson, and Sixth streets as well)

Notice also that unlike the ECI Covered Mainline option where the cap returned to existing grade before the existing southbound Evangeline Thruway, this Cut-and-Cover option massively expands the embankment eastward to the point that the Thruway frontage roads have to be raised nearly 16 feet and straddled to meet the desired sloping profile. The ECI’s proposal for their Semi-Depressed Covered Mainline was to reduce the embankment on the east side that it would return to existing level grade before the southbound Evangeline Thruway, similar to the sloping on the westbound side. Apparently, that was rejected by the LADOTD engineers as too excessive a slope; instead, the embankment extends all the way to the existing northbound Thruway roadway ROW, and even takes on area east of the Thruway between Third and Simcoe streets.

Profile of proposed Cut-and-Cover Johnston St. overpass
(showing insufficient space for return to existing grade level
for at-grade BNSF RR crossing)

The same issues that befell the Semi-Depressed Open Trench option also exist here with the Johnston Street crossing; to which the same solution of an expanded railroad overpass penetrating the Freetown-Port Rico Historic District is offered.

Proposed Cut-and-Cover Johnston St./BNSF RR overpass
based on avoiding FTPRHD penetration
(rejected due to excessively steep gradient)
Revised Cut-and-Cover Johnston St./BNSF RR overpass
adjusted for sufficient gradient
(with penetration of FTPRHD)
Overview of proposed Cut-and-Cover Johnston St./BNSF RR
overpass showing penetration of FTPRHD
The resulting gradients and roadway heights:

Summary of the cross street/frontage system gradient profile
for the Cut-and-Cover concept
Summary of profile heights of roadways/embankment above
ground level for Cut-and-Cover option

And also….the same issues with cross access for Sterling Grove exist as with the Semi-Depressed option, with the same resolutions therein.

Treatment of cross street access for Cut-and-Cover option
near Mudd Avenue/Sterling Grove/Second/Third/Jefferson
(virtually same as Semi-Depressed Open Trench)

Those issues alone would be enough to dissuade the Cut-and-Cover option….but apparently that wasn’t enough for LADOTD. The Tier II Technical Memo report also gives some clear and concise detail of the potential downsides of constructing and operating the surface tunnel, as well as the high costs of maintenance and operation. There would have to be additional considerations for ventilation and egress of trapped vehicles in the event of an incident inside the tunnel. Fire suppression, lighting, and drainage would also have to be dealt with, especially in the event of a major hurricane evacuation through Lafayette. Also, due to Louisiana state law, handlers of hazardous materials would not be allowed to use the tunnel; they would be rerouted through the surface frontage road system.

———————————————————————————-

Conclusion: Comparing The Tier II Alternatives

All of this leads to the ultimate comparison: How do they stack up? The following two tables tells the tale.

First, the displacements and ROW that would be needed:

Displacement and ROW acquisition matrix for all Tier II concepts

As plainly seen, the two Concept 4 options would require less ROW than even Concept 1A (the original 2003 ROD Selected Alternative) due to the elimination of the two direct interchanges, and would have fewer displacements as well. 4-2 (with the boulevard) would use up slightly more takings than 4-1 (the couplet). The Semi-Depressed option (Concept 6-1) would be slightly worse than Concept 1A overall. The Cut-and-Cover option (Concept 6-2), though? Off the charts, with nearly three times the displacements and ROW needed due to the expanse of the embankment needed to cap the tunnel.

Even worse for the Cut-and-Cover option is that LADOTD could only acquire and pay for ROW for those areas used for “transportation purposes”, meaning that other funding sources would have to be located for any property takings outside of the immediate ROW. That would add an additional expense for LCG outside of its otherwise full commitments.

Matrix of 4(f) and Section 106 impact
to Freetown-Port Rico and Sterling Grove Historical Districts
for all Tier II Concept proposals

This is the preliminary impact matrix to the two Historical Districts that the Connector passes near. An Memorandum of Agreement (MOA) is already binding on all parties regarding mitigation for the visual impacts of Sterling Grove Historic District of the originally approved Concept 1A/2003 ROD alternative. More than likely, that MOA will be extended and modified to fit the needs for the new alternative concepts.

It’s likely that the impact will remain the same or even be sightly reduced with the two Concept 4 options, since the shift of the northbound roadway and the adjustments to the northbound connection ramps, combined with the removal of Simcoe Street, do lessen the impact to Sterling Grove greatly. Freetown-Port Rico would not be significantly affected either by the Elevated Option, save for a possible visual impact due to the height of the viaduct, especially if the higher 30′ vertical clearance is chosen.

By contrast, Concepts 6-1 and 6-2 would both require the penetration of the Johnston Street overpass over the freeway and BNSF railroad — a major penetration into the FTPRHD which would probably trigger Section 4(f) protocols for avoidance of impacts to historic properties.

Now, we get to the most important consideration: the cost.

Matrix for comparison of planning level costs for all Tier II Concept alternatives

Keep in mind that these cost estimates are only for the core section between the L&D rail spur and Pinhook Road, not for the entirity of the Connector freeway.

Finally, LADOTD made a comparison matrix rating all the Concepts they studied based on specified criteria. The results are shown below:

LADOTD Comparison Matrix for all Tier II Conceptual Alternatives

As plainly seen, the Concept 4 alternatives, due to their elevated nature, scored higher on the favorability index than the original Concept 1A/2003 ROD Selected Alternative; and both were far higher ranked than the Concept 6 alternatives. Concept 6-2 (the Cut-and-Cover concept) was universally panned for its excessive up-front costs, its high maintenance, its incompatibility with the goals of hurricane evacuation and Haz-Mat material transport, and its excessive taking of ROW and displacements as compared to the Concept 4 (Elevated) concept alternatives. Concept 6-1 (the Semi-Depressed Open Trench option) scored only less slightly worse than the Cut-and-Cover, but still got plenty of red and yellow marks.

Some advocates for the Cut-and-Cover point to the fact that while the front end costs for that option seem prohibitively expensive, the induced rewards for redeveloping the property taken near the ROW would ultimately make for a better economic return down the line. The ECI did do a study on that, claiming that there would be a $6 million a year local tax base return on overall economic development from the Semi-Depressed Covered Mainline option as opposed to the Elevated Mainline option.

Problem is, though, most people don’t think so long-term, and the sticker shock of $818 million for a 1-1/2 mile tunnel will probably be more than enough for most officials to declare the Cut-and-Cover option to be a good idea that just wasn’t good enough. The Semi-Depressed open trench option might be a bit cheaper, but the image of it becoming a flowing tributary of the Vermilion River after a heavy rainfall event may become etched enough in people’s minds to reject that, too.

Which means that it’s becoming more apparent that we are back where we were at the beginning, with an elevated I-49 Connector freeway going through the heart of Lafayette.

Unless some unforseen new environmental impact (such as the possible contamination of the former Southern Pacific Railroad rail yard, or the resolution of the Connector messing with the flight path of Runway 11-29 at Lafayette Regional Airport) was to emerge, the only remaining obstacle to the Connector’s implementation will be the legal firestorm from those opponents who want to kick this project completely out of Lafayette in favor of their Teche Ridge Bypass through St. Martin Parish. I’m sure that the Concerned Citizens for Good Government and the Greater Acadiana Sierra Club are already calling their lawyers for the inevitable second lawsuit that will be filed the day after the Supplemental ROD is delivered for this current study. We’ll just have to watch this unfold.

The I-49 Lafayette Connector and Lafayette Regional Airport: Myths And Reality

One of the many impacts that the I-49 Lafayette Connector freeway project would impose on the city of Lafayette would be a displacement of Runway 11-29 at Lafayette Regional Airport (LFT). This is due to the proximity of converting the existing intersection between the current Evangeline Thruway and East University Avenue/Surrey Street into a grade separated overpass/interchange. The resulting overpass crossing University/Surrey would penetrate into the direct flight path of aircraft entering and departing Runway 11, violating slightly the Runway Protection Zone glide path. The overpass would add about 15 feet of additional height that would need to be cleared along the glide path of Runway 11-29.

In order to raise the glide path to safely avoid the overpass, the proposal is to extend Runway 11-29 by 350 feet at its eastern end, shifting the western end of its approach by that length. This would conceivably provide enough of a graduated slope to clear the overpass and the required 17 foot safe zone above the highest height of clearance. The existing eastern end would not be removed, just remain as sort of a dead zone.

The runway extension would require the acquisition of some wetlands at the eastern end in order to raise the grade level, but the amount of wetland acquisition would be less than 5 acres, and would be within the existing property controlled by the airport.

Aerial view of Lafayette Regional Airport with
proposed displacement of Runway 11-29 to conform with
proposed I-49 Lafayette Connector freeway
(via Lafayette Connector website)

The Louisiana Department of Transportation and Development (LADOTD) and the Federal Highway Administration (FHWA), who are the lead agencies for the Connector freeway project, have had constant and consistent discussion and interaction with the Federal Aviation Administration (FAA) concerning the potential impacts of the runway extension. FAA gave their initial approval to the current alignment and LFT adjustments as stated in the FHWA Record of Decision (ROD) in 2003 (downloadable here), and then authorized and approved their own standalone ROD for the airport modifications in 2008. (The full FAA ROD is downloadable here (pdf document).)

Due to recent changes in FAA regulations for wetland mitigation and construction standards, the current I-49 Lafayette Connector Conceptual Design Study and Supplemental Environmental Impact Statement (SEIS) process does include a reconsideration of modifications to the University/Surrey interchange to mitigate or avoid the need for the runway displacement. It is more than likely, however, that the displacement will be retained due to conditions that restrict modifications to the University/Surrey overpass.

Nevertheless, such developments haven’t stopped opponents of the Connector freeway, who would much rather it be diverted to a bypass around the city, from decrying the possible impacts of the displacement.

One such devout critic is Michael Waldon, whom has dedicated an entire blog (Connector Comments) to documenting his opposition to what he calls “the Con”; and his belief that this freeway project would be the worst thing to happen to Lafayette. I respect his right to oppose this project, but when his arguments are reduced to disassembled claims and distortions of facts, there is a need to correct the record.

And in the case of Lafayette Regional Airport, Mr. Waldon is, as we say, way, way off.

The main thesis of Waldon’s blog post challenging the Connector freeway and the LFT Runway 11-29 displacement falls upon the theory that the 350′ displacement understates by a factor of three the need for a much longer and more destructive runway extension. Essentially, he rips upon the proponents of the Connector for building their project with no concern for “building tall structures next to your airport”. Here’s how Waldon summarizes his beef with Connector proponents:

SUMMARY: The I-49 Connector FEIS identified unacceptable risk due to failure to meet FAA flight path obstruction guidance, resulting from the proposed interchange construction adjacent to the Lafayette Regional Airport. Without documenting calculations or rationale, the FEIS stated that in order to meet these minimum safety requirements, airport runway 11-29 would need to be displaced 350 feet southeast toward Bayou Tortue and the Cypress Island Swamp.

My calculations, based on FAA guidance, arrive at runway displacement considerably longer than that presented in the FEIS. Here, following FAA guidance, I calculated that the required displacement is 860 feet. This significant difference brings into question the economic, environmental, and engineering feasibility of the displacement. Impact of this displacement on flooding, wildlife, and wetlands should be carefully addressed and documented by DOTD.

The public attitude toward airport safety should always be conservative and circumspect. The Airport’s 1975 Master Plan concludes “Conditions at the airport’s periphery make expansion of its land area difficult or expensive or both.” Even beyond the impacts of runway displacement discussed above, it is simply inappropriate to choose to construct any tall structures on the periphery of our airport which is already severely constrained at its location. Tall structures like the University and Kaliste Saloom interchanges constrain future airport runway alignment adjustments, and impact the ability to meet current requirements and future safety requirements should FAA guidance on safety margins or approach slopes change for any reason.

Let’s analyze Waldon’s objections more closely, shall we?

The interchange closest to the glide path of Runway 11-29, as noted, is the University Avenue/Surrey Street interchange. Under the proposed Connector profile, I-49 would cross over University/Surrey at a maximum height of 16 feet, sloping downward to grade level right near where the flight path of Runway 11 crosses the US 90/Evangeline Thruway/Future I-49 right-of-way. The 11-29 glide path parallels and is 200 feet to the south of the Surrey/University centerline. With the adjusted RPZ glide path, the “end” of Runway 11 would be adjusted 350 feet further down from the current endpoint. This picture (from Waldon’s blog) summarizes the adjustment with respect to the current Thruway and Surrey/University.

Overview of Lafayette Regional Airport Runway 11-29,
with adjusted endpoint for displacement (yellow line) and
half of the Approach Surface. (via Connector Comments blog)

Seems foredooming, right? Except, this overview completely ignores the vertical profile. Here is the profile that Waldon uses for his post, taken from the 2002 I-49 Connector Final EIS (downloadable from LADOTD’s Lafayette Connector website here(Vol. 1) and here (Vol. 2)), which he uses for his argument of fear of planes crashing into the University/Surrey overpass.

Vertical profile of I-49 Lafayette Connector alignment
at University/Surrey interchange near LFT (from 2002
Final EIS, via Connector Comments blog)

You can see that the Runway Protection Zone minimum is set at 17 feet above the highest object height; which would put it generally at approximately 30 feet above the ground level of the runway at the point where the 11-29 glide path intersects with the Connector overpass. The RPZ is also sloped slightly to adjust to the slope of the grade of the overpass, thusly extending the RPZ height to cover the overpass as well.

However, that might even overstate slightly the impact to LFT. Here’s a much more recent profile of that section of the Connector freeway, based on the approved Selected Alternative, that was developed in 2007 during the initial Corridor Conceptual Study.

Profile of I-49 Lafayette Connector @ University/Surrey
interchange (from 2007 Conceptual Study, via
Lafayette Connector website)

As you can plainly see, the University/Surrey overpass is now a bit less steeply graded, and the University/Surrey centerline profile is depressed a bit; this must have been to reduce the height of the overpass as to relieve the penetration of the glide path. But, the height in general remains the same: roughly 30′ counting both the height of the overpass and the maximum clearance of 16 feet for vertical clearance for vehicles using the freeway mainline.

It is here where Waldon goes off the cliff. First, he sets up the measurements for FAA and FHWA standards, which is accurate enough.

Finally, it is necessary to estimate the height of objects above the roadway. This could include signs, streetlights, and aircraft warning lights. The FEIS does mention this, and suggests that special signage and lighting may be necessary. Thus, I will assume that the height of the vehicles on the roadway will be the tallest objects above the roadway. There is no Federal vehicle height requirement for commercial motor vehicles (CMVs). Most eastern states, including Louisiana, set a CMV height limit of 13.5 feet on most highways. Louisiana does allow heights of 14 feet on designated highways, and oversize permits can be routinely issued for heights up to 16 feet 5 inches. Without specific guidance from the Louisiana DOTD, it is unclear what height should be assumed. Here, I will simply assume a maximum height of 15 feet for all vehicles and objects on the roadway.

It should be noted that while Louisiana doesn’t have specific height requirements for vehicles using its roadways, Federal Interstate standards do require minimum height restrictions of 16.5 feet for overpasses of freeways, and 20 feet of clearance for covered/tunneled sections. Since the Connector will be an Interstate built as part of the I-49 South extension to New Orleans, I can assume that it will be built to those standards.

Assuming the peak height at the interchange structure controls the required runway displacement, the calculation of length for the approach surface is now straightforward.  The interchange height plus object height has an elevation of 60 feet (45+15). Adding the FAA 17 foot margin of safety gives a total elevation of 77 feet. Subtracting the runway height which defines the primary surface elevation then gives a height of 40 feet (77-37). At a slope of 34:1, the length of the approach surface to the primary surface is 1,360 feet (34×40). At this point along the approach surface, the approach surface width is 1408 feet (1000 + 0.3×1,360), or 704 feet on each side of the extended runway center-line (Figure 3). Adding the 200 foot width of the primary surface at the end of the runway gives a total distance form the peak of the interchange of 1,560 feet. The present distance is estimated to be 700 feet, so the total runway displacement required would be 860 feet (Figure 4). This is 510 feet longer than the value asserted in the FEIS. This difference significantly brings into question the economic, environmental, and engineering feasibility of the displacement.

The highlighted portion of Waldon’s quote gives his game away. 60 feet??? Really? But, I thought that the height of the University/Surrey overpass was only 12 to 15 feet; how did Waldon get to 40 feet? Simply, he gets his interchanges mixed up. The adjacent Kaliste Saloom Road interchange with the Connector freeway and the frontage roads does indeed include a 40 foot high ramp that is needed to clear the freeway mainline, the adjacent BNSF/UP railroad line, and another high ramp. There is one slight little problem, though; the Kaliste Saloom interchange is nearly 3,000 feet away from the RPZ glide path of Runway 11-29; and the offending ramp drops down to grade level to split to connect with both the northbound Connector mainline and the northbound frontage road long before it gets to the Runway 11-29 flight path. Here’s an overview, straight from the 2007 Conceptual Study:

Aerial profile of I-49 Lafayette Connector @
Kaliste Saloom Road & University/Surrey
interchanges & LFT (from 2007 Conceptual
Survey, via Lafayette Connector website)

As plainly seen from this profile, the Kaliste Saloom ramps are so far away from the Runway 11-29 glide path that it would take some very, very, very bad aircraft control for any plane to even threaten to hit even the highest overpass.

But, it doesn’t stop Michael Waldon from using the Kaliste Saloom ramps for his equation which concludes that a much steeper gradient for 11-29 would require a much longer runway displacement (860 feet, compared to the 350′ proposed in the ROD). This would require a much longer extension of 11-29 that would not only consume far more wetlands, but potentially threaten Bayou Tortue, a tributary that sets the boundary between the airport property and the surrounding wetlands. This is the proof that, in Waldon’s eyes, disqualifies the Connector as a valid alignment, and justifies his belief that a bypass would be much better for Lafayette.

If we adjusted Waldon’s measurements to reflect the reality of the University/Surrey overpass rather than his fantasy of placing the Kaliste Saloom ramps in front of the airport, they would be as follows:

Interchange height (16 feet) + maximum surface height (16 feet) = 32 feet (compared to 55 feet)

Add FAA 17 feet clearance zone = 49 feet (compared to 77 feet)

Subtract 37 feet for primary surface elevation height: 49 – 37 = 12 feet (compared to 77 -37 = 40 feet)

Length of approach surface to primary surface, using 34:1 slope: 12 * 34 = 408 feet (compared to 1,360 feet)

Add 200 feet overrun = 608 feet (compared to 1,560 feet)

Account for current 700 foot length of Runway 11-29: 92 feet of existing leeway (compared to shortage of 860 feet)

In other words, the existing Runway 11-29 is actually marginally suitable for adjusting to the glide path changes from the University/Surrey overpass, but it would be a rather tight fit. The 350 foot runway extension/displacement would certainly add the necessary margin of safety, and would be the maximum allowed that would least impact the adjacent wetlands and Bayou Tortue.

As I mentioned before, the recent changes in FAA regulations regarding construction of runways over wetlands has prompted the FHWA and LADOTD to reconsider modifying the University/Surrey overpass to possibly avoid displacing the RPZ glide path. (Listed as Potential Design Modification #10; the full list of proposed modifications can be found here.)Such a study, though, does not avoid the basic fact that, even with the wetland impact, the runway displacement would not be anywhere near the destroyer of Lafayette that folk like Michael Waldon would assume it to be.