The George Washington Bridge was the world's longest suspension bridge when it opened in 1931 with six lanes.

Two more were added in 1946, followed by the construction of a six-lane lower level in 1962, making it the only 14-lane suspension bridge on Earth.

With the George Washington Bridge approaching its 100th birthday, crews are working hard on a 15-year endeavor to modernize the structure, an important link between New York and New Jersey.

The Restoring the George program, a $2 billion effort made up of 11 projects, started in 2015 and is expected to run until 2030. Four of the projects have been completed and six more are active today, said Ken Tripaldi, senior engineer of construction for the Port Authority of New York and New Jersey.

Among the current projects are the replacement of 592 steel suspender ropes supporting the roadway and the rehabilitation of four main cables spanning the length of the bridge. This marks the first time either has been renovated since the structure was built in 1931.

Records show that about 300,000 vehicles cross the bridge every day, he said. Thus, each phase of the restoration program is extensively coordinated to minimize traffic disruptions.

Typically, there are 100 to 200 workers at the bridge five to six days per week, Tripaldi said. That includes crews operating at night, when Port Authority officials often close multiple lanes to allow for more work.