A. Murray MacKay Bridge

The A. Murray MacKay Bridge, known locally as "the new bridge", is a suspension bridge linking the Halifax Peninsula with Dartmouth, Nova Scotia, and opened on July 10, 1970. It is one of two suspension bridges crossing Halifax Harbour, the other, Angus L. Macdonald Bridge having been completed in 1955. The bridge carries on average 52,000 vehicle crossings per day.As of April 1, 2011, the toll charge to cross for regular passenger vehicles is $1.00 cash or $0.80 with the MACPASS electronic toll system (60¢ tokens were once used but are no longer accepted as of May 1, 2008). Larger vehicles have higher tolls proportional to the number of axles. The Halifax-Dartmouth Bridge Commission is exploring the idea of moving entirely to electronic tolls to avoid handling tokens or cash. The A. Murray MacKay Bridge is the only harbour bridge which permits semi-trailers and large trucks. Pedestrians and bicycles are not permitted on the A. Murray MacKay Bridge; they may use dedicated lanes on the Angus L. Macdonald Bridge instead.DesignThe bridge measures 1200m with the total of all suspended spans being 739.9m in length, carrying four traffic lanes with posted speed limits of 70km/h. It was designed with a maximum road gradient of 4 percent. It is notable as having been the first bridge built in North America using an orthotropic steel deck, which yielded a completed structure having half the overall mass of the Macdonald Bridge nearby. Engineering of the bridge also employed the pioneering use of wind tunnel testing which considered the impact of winds on the structure both during construction and when complete.