GONZALES — On the busy La. 30 corridor in Gonzales, traffic headed for Cabela’s, Tanger Outlets mall, St. Elizabeth Hospital and hotels must contend with workers and big rigs trying to reach Ascension Parish’s chemical industry on the Mississippi River.
State highway officials for more than two years have been studying how to improve traffic flow in the La. 30 area as the traffic combination has created competing demands for the area’s future.
It posed a challenge for state transportation officials and their consultants as they searched for solutions that could last for 20 years for the corridor stretching from Ashland Road outside Gonzales, past Interstate 10 to La. 44 south of the city’s heart.
Jody Colvin, a state Department of Transportation and Development traffic engineer, said Tuesday that with 2 percent to 2.5 percent annual growth in traffic volume projected for the corridor, none of the early concepts worked for more than two decades.
But at the Gonzales Civic Center Tuesday, DOTD officials unveiled three concepts they say can handle that kind of growth, though the agency has not yet stated its preference nor determined which handles the traffic best.
“I mean, I like everything I see,” said Gonzales Mayor Barney Arceneaux, who has been waiting on DOTD to finish its study. “The only thing I was hoping is that we would have a final decision today. We are not apparently going to have a final decision.“
All three versions would employ J-turns, raised medians and other measures to reduce the number of left turns along La. 30. They also anticipate widening the highway from two to four lanes where needed.
But the versions diverge from there, in some cases in their handling of the I-10/La. 30 interchange.
One alternative anticipates a major use of roundabouts at intersections along the entire corridor, like a string of pearls, but the roundabouts would need to work in conjunction with a new industrial highway to help with capacity.
That highway would link La. 30 west of the entire corridor with a new I-10 interchange at Cornerview Road, also known as La. 429, plans show.
Roundabouts are controlled-access, circular intersections that DOTD officials have been promoting heavily for the past several years due to their safety and ability to slow traffic speeds while also allowing continuous flow.
Colvin said the roundabouts, with only four lanes and a median throughout the corridor, would allow visitors to walk among the area’s hotels, restaurants and retail outlets.
Another alternative would use something called a diverging diamond interchange through the I-10 area, plans say.
Multiple lanes of La. 30 traffic moving under I-10 would switch to the opposite sides of the road, then switch back to the normal side once clear of the interchange.
Colvin said the interchange is designed to handle heavy left turn movements efficiently. By flipping which side the traffic moves on, all those left turns become like right turns in that they happen with the flow of traffic.
A third alternative would employ more standard improvements to the I-10 interchange.
The alternatives using the diverging diamond interchange and the more standard I-10 interchange would require six lanes on La. 30 west of I-10 and traffic lights. The roundabout version would stay with four lanes, which Colvin said necessitates the link to a new I-10 interchange. Roundabouts don’t have traffic lights.
As with many DOTD projects at this early stage of review, total cost and total funding for any of the options are unknown.
Colvin acknowledged it’s likely the roundabout alternative would be the most expensive because, though the option would need less right of way along La. 30, the alternative anticipates building a new highway and I-10 interchange.
Arceneaux and other city officials have long preferred the roundabouts due to what they see as their demonstrated track record in moving traffic and in improving safety.
Ascension Parish President Kenny Matassa, a former longtime Gonzales city councilman who served while the corridor improvements were being developed, said he also favors roundabouts.
At the same time, Arceneaux said he is open to other alternatives if they can be shown to move traffic and improve safety.
Some visitors Tuesday said they wanted more lanes and J-turns and didn’t want to see roundabouts on La. 30.
“That’s going to be nothing but one big headache,” said Ray Hall, 71, who lives off La. 30 east of La. 44.
Hall said that years ago, he used to contend with congestion in a former traffic circle at the foot of the Huey P. Long Bridge in Jefferson Parish.
Some business people were also concerned about roundabouts.
Pete Graffagnino, comptroller for Roland J. Robert Distributor Inc., which owns a Chevron gas station on La. 30, said he doesn’t favor roundabouts.
“Get all the loop-de-loops out. Only six lanes and four lanes, and that’ll work,” Graffagnino said.
Colvin said DOTD doesn’t expect to finish the feasibility process until the end of year, though two short-term projects are expected to be bid for construction in late 2016.
One would add an extra eastbound lane on La. 30 between Ashland Road and Cabela’s Parkway while another would add a left turn lane at La. 30 and Veterans Boulevard.