The A19 Tees Viaduct or Tees Flyover is a six-lane dual carriageway road bridge in the North East of England carrying the main A19 trunk road north-south across the River Tees. It is situated between Middlesbrough and borough of Stockton-on-Tees just north of the A19's interchange with the A66 trunk road. The Teesdale Way long-distance footpath, the Tees Valley Line, the B6541 (Old A66/A67, Stockton Road) and the A66 pass under the bridge on the southern bank of the Tees. The bridge was built with sufficient clearance to allow ships to pass, although the port of Stockton-on-Tees up-river was virtually redundant by then. Since the Tees Newport Bridge had its lifting deck permanently fixed in the down position in 1990, large shipping can no longer reach the Tees viaduct, further reducing the need for such a high structure.
The bridge was constructed from 1973 to 1975 and opened in 1975. It is made of reinforced concrete piles, steel-plate girders and a composite deck and is the largest such bridge in the British Isles.
There have been problems with corrosion since the bridge was opened and repairs have been necessary at times. Expansion joints were cracking and allowing de-icing salts to wash from the bridge carriageway into the piers, cross beams and columns giving rise to extensive chloride attack and it was decided the best solution was the complete demolition and reconstruction of most of the piers and repair of others. From 1988 the underside was enclosed with a steel and GRP panelling structure to protect the primary structure from the effects of weather and to allow safe and easy inspection and maintenance.
The bridge now carries some 70,000 vehicles a day and there are concerns that the capacity of the road is being exceeded at peak times Because of this CCTV cameras were installed on the bridge to record incident related congestion and respond more quickly. In 2006 the detailed principal inspection report concluded that the Tees Viaduct is overall in fair condition.