Princess Margaret Bridge

The Princess Margaret Bridge, sometimes called the Princess Margaret Rose Bridge or shortened to just PMB, is a 2-lane highway bridge crossing the Saint John River at Fredericton, New Brunswick, Canada. It is named after HM Queen Elizabeth II's sister HRH The Princess Margaret, Countess of Snowdon.

Constructed as a steel truss structure, the bridge measures 1075 m (0.7 mile) in length and has a navigation clearance of 25.6 m (85 ft) in the centre. It opened in 1959 as part of the Route 2 Trans-Canada Highway bypass project around Fredericton. Following a realignment of Route 2 in 2002, the bridge now carries Route 8, the primary Fredericton-Miramichi highway.

Safety concerns have precipitated many construction projects on the bridge in the 1980s and 1990s due to the narrow width of the roadway and high traffic volume and the bridge deck is prone to severe icing conditions in winter, leading to motor vehicle accidents. The bridge's narrow, two-lane span poses a hazard for motorists travelling at speeds over the posted speed limit of 70 km/h (45 mph).

The approaches to the bridge on both sides are also of concern:

The southern approach descends a steep grade while transiting from a 4-lane divided freeway to 2-lane suburban/rural arterial road. Pedestrians from a St. Thomas University residence on the east side of the bridge frequently take a shortcut at grade across the highway up the hill from the bridge to follow the contour of the hill while en-route to the university's main campus. The southern approach also contains a modified clover leaf interchange with Forest Hill Road with very tight turning radius on exit and entrance ramps. Northbound travellers go down a sharp incline and around a 30-degree turning radius to access the bridge. On three occasions, tractor trailers have failed to negotiate the turn, instead crashing through the guard rail and either dangling over the edge or falling into the river entirely.

The northern approach follows the old Trans-Canada Highway alignment toward Barker's Point (now designated Route 105), but travellers wanting to continue on Route 8 must exit on a ramp immediately after leaving the bridge, while maintaining another sharp turning radius to pass back under the roadway and follow the Route 8 alignment to Marysville. This interchange is envisioned to be replaced by a straightened alignment of Route 8 onto the Marysville By-pass with a newly designed interchange with Route 105.