In a cable-stayed bridge, instead of hanging the roadbed from cables slung over towers, the cables run directly between the roadbed and the towers. Although cable-stayed bridges have become common in Europe since World War II, they are relatively new to North America.
The bridge, designed by Swiss civil engineer Christian Menn, follows a new design in which two outer lanes are cantilevered outside the towers while another eight lanes run through the towers. It has a striking, graceful appearance.
The bridge is within view of the Bunker Hill Monument. Its name commemorates both the battle and Boston civic leader Leonard P. Zakim, whose theme was "building bridges between peoples". Although the bridge was completed in 2002, it was not opened to traffic until the northbound Central Artery tunnel opened in early 2003. The cantilevered northbound lanes (a two-lane entrance ramp) are scheduled to open in 2005, when the old bridge has been sufficiently demolished to allow for their completion. The southbound lanes are scheduled to open in early 2004 with the opening of the southbound tunnel.