A 1.5-mile section of proposed Interstate 49 near downtown Lafayette will cost between $355 million and $668 million, depending on the design.
The I-49 Community Working Group received that news Thursday evening from consultants working on the I-49 connector project for the Louisiana Department of Transportation and Development.
Several design concepts for the section of interstate between Pinhook Road and the railroad spur were eliminated in August, leaving two series of designs, one featuring an elevated interstate with slight differences among them and a second series with a semi-sunken interstate or a tunnel.
Since the last meeting in August, the consultants studied each element of each design concept, eliminating those that didn't work for various engineering reasons, Steve Wallace of consulting firm Stantec said. They then combined the remaining ideas into four options that were presented Thursday.
The tunnel would be the most expensive, require removal of the most homes and businesses, and present the greatest challenges for emergencies and drainage, the consultants' comparison suggests.
It would cost about $668 million to acquire rights of way and homes and businesses, and to build the tunnel design, Wallace said. A semi-depressed option would cost about $468 million, while two elevated options would cost $355-363 million without the signature bridge option.
Johnston Street is a problem for the tunnel and semi-depressed designs since it would have to travel over either option. The incline and decline, or grade, of Johnston Street is problematic since designers are trying not to have the road infringe on newly-designated historic district Freetown/Port Rico.
No action was taken on the refined design concepts Tuesday. They will be presented to a Technical Advisory Committee and Executive Committee Friday.
Next week, the groups are scheduled to meet again to receive evaluation results of 24 other potential design modifications that consultants have been studying, according to John McNamara, also with Stantec. In December, he said, they expect to finalize the design alternatives and by early 2017, have a selected concept to move forward for further consideration.