Witnesses estimated Caleb Batiste was going between 70 and 75 mph about 6:20 p.m. Thursday when his 1997 Honda motorcycle rode up on the inside curb of the southbound Lake Pontchartrain Causeway.

When the racing bike came off the curb, Batiste lost control.

The 1100cc motorcycle came to a stop near the inside railing. But Batiste didn’t, according to Carlton Dufrechou, general manager of the Causeway.

Batiste, 19, broke several bones and lost a lot of blood while on the bridge, Dufrechou said. First responders from Jefferson Parish took him to Interim LSU Hospital in New Orleans, where his condition has stabilized, Dufrechou said.

A hospital spokeswoman said Batiste’s condition was “fair.”

Batiste is “unbelievably fortunate to be alive,” Dufrechou said.

Batiste’s crash shut down the southbound Causeway until about 9 p.m. while workers cleaned up a nearly half-mile trail of debris from the accident, Dufrechou said.

The northbound bridge was also closed to allow drivers stuck on the southbound span to turn around and head back toward the north shore, Dufrechou said. The northbound span was reopened about 8 p.m.

For more than a year, Causeway officials have been discussing ways to improve the bridge’s safety. The focus of those discussions has been on the rails that line the older southbound span.

Those rails — which are 6 inches lower than those on the northbound span — do little to hold modern vehicles on the bridge, which has led to an increasing number of crashes in which a vehicle goes into Lake Pontchartrain, usually resulting in death.

Dufrechou said speed may have played a role in Thursday’s crash. But the biggest culprit in Causeway accidents usually is drivers who are not paying attention, he said.

“Use the clump-clump-clump of the bridge joints to help reset your brain,” he advised drivers.

Follow Faimon A. Roberts III on Twitter, @faimon.