The steel arch bridge was completed in 1931 after three years of construction, and is designed by master architects Othmar Ammann and Cass Gilbert. The main span is 510 meters long and was the world's longest from the day of completion to 1977, when surpassed by New River Gorge Bridge. Currently Bayonne Bridge is the world's 3rd longest arch bridge. The deck is 46 meters above water level from the highest point and carries an average of 23,400 vehicles a day across the Kill Van Kull strait. In this model, the number of support columns on the approach ramps is reduced to half of the original number, to simplify the already complex model.