The freeway ends at a large interchange with the Trans-Canada Highway, Highway 417 (Exit 131), just south of the Lakeview and Bayshore communities on the Ottawa River; downtown Ottawa is to the east and Kanata is to the west. Design features The Stony Swamp overpass at the southern entrance to Ottawa is a pre-tensioned concrete arch; the design, which allows the structure to cross the entire right of way with a single span, won the 1996 Award of Excellence from the Portland Cement Association. The bridge acts as a gateway to the National Capital Region and is the longest rigid frame bridge in Ontario with a span. In the same vicinity, the freeway sinks below ground level in a trench; groundwater-retaining walls were installed to prevent the lowering of the water table in adjacent wetlands, therefore mitigating damage to them. At the Jock River, southwest of Barrhaven, deposits of sensitive leda clay presented a challenge in designing the crossing for the freeway as well as the Canadian National Railway overpass to the north. It was feared that the weight of these structures could destabilize the clay deposits beneath and lead to landslides. In place of the standard heavier aggregate, lighter blast furnace slag, at half the weight, was substituted. Sloped rock cuts line the side of the freeway in numerous locations. With the intent of reducing the severity of collisions against those cuts, the Ministry of Transportation of Ontario (MTO) tested out numerous alternatives to strike a cost-to-benefit balance. The standard slope used by the MTO is vertical, offset from the edge of the pavement by . The study concluded that although an initially higher investment would be required, the 2:1 sloped cut with grass overlaid produced the best results. History Highway 16 New In 1966, the Department of Highways (DHO), predecessor to today's MTO, published the Eastern Ontario Highway Planning Study, identifying the need for a controlled-access highway between Ottawa and Highway 401. Highway 16, which passes over the geologically subdued St. Lawrence Lowlands, was selected over Highway 15, which crosses the undulating Canadian Shield to the west, as the ideal route for the new link. Highway 16 was one of the first roads taken over by the expanding Department of Public Highways in 1918. The important corridor between the Trans-provincial Highway (Highway 2) and Ottawa was known as the Prescott Highway. In 1925, the road was given a