For more information go to Other than transit buses, no vehicles weighing over 3200 kg (7055 lb) are permitted on the Macdonald Bridge vehicles in excess of this weight limit must cross the harbour via the MacKay Bridge. The first time was on the Lions Gate Bridge. It is only the second time ever that the suspended spans of a bridge will be replaced while being open for traffic during the day.
Once complete the only original components on the suspended structure will be the main cable, the two towers, the anchor piers and cable bents. In 2015 the suspended portion of the bridge will be replaced: that includes the floor beams, the stiffening trusses, road deck and suspender ropes. The Macdonald Bridge often suffered from traffic problems due to its narrow width, so a lane addition project was completed in 1999. The bridge was designed by Phillip Pratley, a bridge designer also responsible for the Lions Gate Bridge in Vancouver. Macdonald Bridge, known locally as the Macdonald Bridge or the "old bridge", was opened on April 2, 1955. The Commission's toll rates are approved by the Nova Scotia Utility and Review Board.
The Commission has nine board members, five of whom are appointed by the Province, including the Chair and Vice-Chair the Halifax Regional Municipality appoints four Councillors for the remaining seats on the board. The Commission reports to the Minister of Finance and the Nova Scotia Cabinet approves the Commission's financing. In March 2009 the Commission launched its current operating name, Halifax Harbour Bridges, as well as an updated logo. The Commission also maintains authority over any other bridge or tunnel structures crossing the harbour limits, including across the Northwest Arm, although no such bridge or tunnel currently exists. The Commission is responsible for constructing, operating, maintaining two suspension bridges that cross Halifax Harbour between the communities of Halifax and Dartmouth.
The Halifax Dartmouth Bridge Commission was created in 1950 by a statute of the General Assembly of Nova Scotia and currently operates under a new statute passed in 2005 named the Halifax-Dartmouth Bridge Commission Act.