I-12: LA 21 - LA 59 (H.011137 & H.011152)

DOTD proposes to widen Interstate 12 (I-12) from approximately 1.2 mile west of the Louisiana Highway 21 (LA 21) interchange continuing eastward to the LA 59 interchange north of Mandeville, Louisiana in St. Tammany Parish. The project area begins at 30.4471, -90.1408 and ends at 30.4113, -90.0374.

Currently, I-12 consists of two travel lanes in each direction. The project would include widening the pavement surface into the median, overlaying the existing lanes with asphalt, and installing concrete median protection. Some relatively short sections that are sagging will be completely reconstructed with new pavement. The project will also include auxiliary lanes connecting Pinnacle Parkway across the Tchefuncte River to US 190, and the US 190 and LA 59 interchanges. Pavement striping, raised markers, and rumble strips would also be installed. A concrete median barrier would also be installed in portions of the project corridor. Openings in the barrier would be located at interchanges, in forested areas of the median, and at approved median crossings.

Clearance heights on the current Tchefuncte River bridges will be maintained. The Tchefuncte River is listed as a Scenic River; therefore, a permit will be required prior to bridge construction. The project proposal includes the widening and replacement of all bridges and overpasses.

Two lanes in each direction would remain open to traffic during construction. Any lane closures limiting traffic to less than two open lanes would occur at night and would not be continuous throughout the project corridor.