Lake Pontchartrain Causeway retaining wall designs to be put to the test

In an instant, one man's recent afternoon trip across the Lake Pontchartrain Causeway was transformed from monotonous drive to terrifying ordeal. The motorist lost control, and his pickup truck hit the left wall of the southbound span, careened across the lanes and struck the right wall before plummeting into the lake.

Christian Pate, 26, of LaPlace was lucky to survive the ordeal. Others haven't been so fortunate.

But the May 31 accident was similar to many of the other incidents in which vehicles have vaulted into the lake since 1995.

All 11 accidents took place on the Causeway's southbound span, whose concrete retaining walls stand 25 inches high from the roadway, some 6 inches lower than those on the newer northbound span.

Most involved inattentive drivers behind the wheel of large pickups or SUVs. And in most cases, the vehicle hit at least one wall before ricocheting across the span, climbing the opposite wall and flying over the side, authorities said.

Next month, members of the Texas A&M Transportation Institute will visit the 24-mile bridge to begin testing some of the design options they've come up with to improve the southbound span's retaining walls and prevent vehicles from vaulting into the lake.

Bridge officials have long fretted about the safety issue on the span, and the Causeway Commission voted last December to spend up to $100,000 to hire the institute.

Tests will be conducted on two basic designs that call for adding steel posts and railings atop the existing concrete walls.

One option features 21-inch tall steel posts and two steel railings that would be bolted atop the concrete wall and stand 46 inches above the roadway. Tests will be done on two varieties of this design, the difference being the thickness of the base plate.

The second design calls for steel posts and single rail that would increase the height of the existing barrier by 12 inches, bringing it to 37 inches above the road.

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Lake Pontchartrain Causeway retaining wall designs to be put to the test