GONZALES — Perhaps a decade from now, 18-wheelers headed to Ascension Parish's industrial corridor will use a new Interstate 10 interchange and access road shooting them onto La. 30, the main street of parish chemical plants in Geismar.

The proposed I-10 interchange southeast of Cornerview Road and related connector roads are receiving renewed scrutiny from state highway officials as parish government officials continue negotiations with major landowner and home builder, Grady Melancon, who owns the more than 600-acre Buzzard Roost property crucial for the plan to come to fruition, the officials and builder have said.

State highway officials say the interchange and related roads would improve traffic flow on La. 30 around its current interchange with I-10 by routing commercial traffic away from that section of the two highways.

The area is already home to Tanger Outlets Mall, Cabela's, Home Depot and other stores and restaurants with traffic that doesn't always mix well with big rigs, tanker trucks and commuting plant workers.

Industry groups have advocated to see improvements to the La. 30 corridor west of I-10 because, they say, continued worsening of congestion could endanger the local plants' ability to win new capital investment.

Access to that area, besides the current I-10 interchange at La. 30, is limited: River and Ashland roads, La. 73, and a parish connector route near Lamar-Dixon Expo Center that recently had its final segment finished.

Completed in October, a state Department of Transportation and Development study found the combined I-10 interchange and new access roads to La. 30 and also La. 73 in Geismar would improve traffic flow in combination with other projects also on the books.

The study estimated the costs of two relatively similar alternatives for the access roads at nearly $58 million to $63.2 million in 2020 dollars. In 2015, the interchange itself was estimated to cost another $35 million but could be tens of millions of dollars more.

Connie Porter Betts, the DOTD transportation planning administrator, informed Ascension council members this week about the status of the proposal.

She said DOTD decided to take another look at the I-10 interchange concept. Other studies looked at adding new traffic lanes to La. 73 and La. 30 at their intersections with I-10, but those new lanes would have posed significant impacts to nearby homes and businesses. Both highways have significant commercial development along them near I-10.

"Ultimately, it was determined that additional interchanges would need to be considered," Betts said.

DOTD dusted off the Cornerview Road plan. The I-10 interchange has been in a long-term state highway plan for so called "megaprojects" since at least 2015 but has no funding source identified, DOTD plans say.

She told the council that officials were planning to start the next phase of analysis, an environmental study, that could take up to three years to hire a consultant and do the work.

The first step after that study is finished, should it further justify the project, would be preserving land for the future road corridors, DOTD plans say.

Melancon, president of Sorrento Lumber Co. and a manager of the development company SLC LLC, was expected to seek approval from the parish Planning Commission to turn a more than 120-acre section of the Buzzard Roost property into an industrial park. 

Parish planning officials have raised worries about the park's impact on access to La. 30 for the I-10 Cornerview plan and have asked Melancon to provide his overall road master plan for the Buzzard Roost site.

Melancon's SLC bought the property, once the old Hughes ranch, in March 2017 for $3 million, land records show. SLC has gradually made moves to start developing it, receiving a contested industrial zoning for part of it in December 2017 that set aside a residential buffer zone near existing homes on West Robert Wilson Road. 

Melancon, who couldn't be reached at Sorrento Lumber or through one of his engineering consultants, has discussed graduating development of the property from light industrial in the south to residential in the north, away from chemical facilities.

In an interview with The Advocate late last year, Melancon said he has been negotiating with parish officials and was open to helping provide the routes for the future interstate connections but didn't want those negotiations to go on so long — as in years — that they would slow his long-term plans.

He said he recognized the economic benefits the access routes would bring for his property.

Under conceptual plans Betts presented Monday, the proposal would be would have three legs that would be built in phases due to funding constraints.

First would be a more than mile-long, north-south link from La. 30 that would become part of a new La. 429, rerouting that highway from its current route as Cornerview Road along the banks of New River Canal.

Those plans show the connection to La. 30 would avoid where Melancon plans to build his park but run behind homes on West Robert Wilson. The supplanted portion of Cornerview, a winding, narrow, two-lane road that has had deadly crashes through years, would become a parish road.

The second phase would build another new leg of La. 429 from the northern end of the new north-south route northeast through largely vacant land in the Kling Road area between Lula Lane and Armond Drive.

The new route would intersect with I-10 and head farther east to reconnect with Cornerview Road. The I-10 interchange would be built at this phase.

Third phase would build the connection west to La. 73, covering about 1.62 miles, plans show.

The state feasibility study also anticipated building other local roads, having local developers build some roads and widening to three lanes existing parts of Cornerview Road that remain a state highway. 

The latest state study of the idea would not only narrow down land that would need to be purchased but also try to establish the technical need for the future interchange so federal highway officials in Washington would authorize its construction.

Jamie Setze, executive director of the Capital Region Planning Commission and a former federal highway official, said that process could take more than the three years that Betts estimated, due to the complexity and review in Washington.

In years past, Ascension officials have lobbied for a new interchange at La. 74 in Dutchtown, north of where the Cornerview interchange would be built.

Setze said he believes that in the coming decades, I-10 between Baton Rouge and New Orleans is likely to add only one new interchange and it will be in Ascension. He said he has advised local leaders to figure out which would be the best.

State Sen. Eddie Lambert, R-Gonzales, said the La. 74 and Cornerview interchanges serve different needs: one for commuter traffic and one for commercial traffic.

"If you ask me which one is the best, I don't know if I can tell you because they're both good, and they both address issues that need to be addressed," he said. 

Email David J. Mitchell at dmitchell@theadvocate.com

Follow David J. Mitchell on Twitter, @NewsieDave.