The federal government has approved a $3.9 billion bridge over the St. Lawrence River in New Orleans that could see construction begin as early as 2021, but a safety panel has found the project’s design is too complex and expensive.

The panel recommended that the $2.2 billion bridge be completed over the river by 2024 to allow for the installation of new sensors that would help prevent a cascade of cascades.

The $2-billion bridge is designed to carry traffic on two lanes each way, with an on-street parking lot and pedestrian crossing.

The bridge would span the river from a bridgehead in St. Louis to the Louisiana border.

The federal project is expected to cost $1.9-billion, but that number is projected to rise as the cost of the sensors, as well as other infrastructure, is factored in.

The cost of a $5.9 million sensor that would allow pedestrians to cross over the bridge was more than $400,000, the Federal Aviation Administration estimated in a 2016 report.

The new sensors would also have to be installed to monitor and control the flow of the river.

A review of the cost-benefit analysis by the Federal Highway Administration and the Department of Transportation found that the bridge is not financially feasible.