The announcement this week that more studies are needed on the impact of building Interstate 49 through Lafayette has supporters fearing for the future of the project.

A more thorough analysis sets the stage for a new round of public meetings and studies and raises the possibility of federal authorities revisiting their 2003 decision to sign off on the project.

“It is very sad. At a minimum, the project is delayed,” said Kam Movassaghi, a longtime supporter of the I-49 Connector through Lafayette and a former secretary of the state Department of Transportation and Development.

DOTD officials said the decision to pursue further impact studies was made after recent consultations with the Federal Highway Administration about a list of I-49 design proposals that has expanded in recent months from one to 19.

At issue is the need for a supplemental environmental impact statement. It means DOTD will revisit the original environmental impact statement for the I-49 Connector — a broad study of how the interstate would impact the community. It touches on traffic, road noise, safety, air pollution, historic neighborhoods, environmental contamination, trees, waterways, pedestrian pathways and a host of other issues.

The original environmental impact statement was finalized in 2002 and served as the basis for federal officials giving their formal stamp of approval for the planned interstate in 2003 through a record of decision.

Without a record of decision, there is no interstate, and one concern among I-49 supporters is that revisiting the old environmental impact statement ultimately means revisiting the record of decision.

Federal officials will have to look at the new impact study and decide whether the old record of decision, or an updated version, is still valid. They might say everything is fine, but they might not.

“We always said we didn’t want to open the ROD,” Movassaghi said. “Once you open the ROD, at the other end, you don’t know the outcome.”

It’s a particular concern for Movassaghi and others because opposition to the I-49 Connector is organized, vocal and active.

Gauging the overall support or opposition to the connector is difficult — there are loud voices on both sides — but the project generally has received strong backing from the business community.

In a statement issued this week, Jason El Koubi, president and CEO of the regional economic development group One Acadiana, said the new analysis for I-49 will “delay urgent investments,” and he urged supporters to become more active to keep “a small but vocal group” from killing the project.

“If you’re as tired as I am about these delays, it’s time to say loudly and clearly that we need to move forward with urgency,” El Koubi wrote.

On the other side, I-49 opponents have not all welcomed the announcement about supplemental environmental impact statement, arguing it will not go far enough and that the entire project needs to be reconsidered in favor of building I-49 around the city or not at all.

DOTD revived planning for the 5.5-mile connector through Lafayette last year after a gap of more than a decade since the last serious public discussion about the design of the road, which would generally follow the path of the Evangeline Thruway.

The state agency first focused on a preliminary interstate design done years ago, but in recent months, the range of options has expanded to 19 concepts, including versions that remove downtown interchanges and some that call for the interstate to be sunk below ground level, with local streets crossing over it.

Many of those tweaks were sought by residents who don’t oppose the connector in general but do oppose a conventional elevated interstate with sprawling interchanges that some fear might divide the community and foul local traffic patterns.

DOTD cited the expanded range of design options in explaining the need for the supplemental environmental impact statement.

Movassaghi said those options likely strayed too far from the interstate plan federal officials approved in 2003.

“The request for changes were so massive they didn’t qualify as small tweaks,” he said.

But there have been other significant changes since the 2002 environmental impact statement: recognition of a new historic area, a new interest in redevelopment of some of the neighborhoods along the planned route, a keener interest in pathways for pedestrians and bicycles and a shift in thinking about how big roads can hurt or help communities.

In some respects, the need for a supplemental environmental impact statement is not unexpected.

Revisiting impact statements is not uncommon for projects that have aged without action, and DOTD recognized the possibility last year when it laid out work details for the consultants overseeing planning for the interstate.

What is certain is discussions of the various design alternatives will be more formalized going forward to adhere to federal guidelines, but it is unclear what shape those discussions may take.

The meetings of I-49 committees tasked with evaluating design alternatives have been put on hold pending a yet-to-be-scheduled public meeting to receive comments on all 19 design alternatives, said DOTD spokeswoman Deidra Druilhet.

She said DOTD initially had projected having a selected design by summer 2017, but the target has now been pushed back until spring 2018.

“We are adding about a year to the process,” she said.