Hogg's Hollow Bridge

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Hogg's Hollow Bridge is a set of four separate highway bridges that span the Don River Valley and carries the eastbound and westbound traffic of Highway 401, split into collector and express lanes, in Toronto, Ontario.

With a 14-lane cross section (6 collector lanes, 8 express lanes), it is by far the busiest multi-span bridge in North America, surpassing the Brooklyn Bridge.

The inner bridges were constructed in 1929, as Avenue Road, and incorporated into the Highway 401 routing in the 1950s. It underwent a major rehabilitation in the early 1980s. Though the inner bridges are right next to each other, appearing as a single structure, there are two separate road decks.

The collector (outermost) bridges were built in the late 1960s during the widening of Highway 401 to a collector-express system. A conventional lighting system with truss-neck poles was added to the bridges (and the rest of the widened 401) around this time.

The road surface and decks require constant maintenance due to the wear and tear from high traffic volumes. Since 2001, an Ontario tall-wall concrete barrier has replaced the steel guiderail in the median separating eastbound and westbound traffic. The late 1960s conventional truss lights have replaced by high-mast lighting. From 2002, the outermost bridges have also undergone rehabilitation (replacing road surface, guide rails and/or concrete barriers). The westbound collector traffic has been rehabilitated; the project included the north side outer bridge and the Yonge Street overpass. Starting in 2006, the eastbound collector lanes are being re-built and the reconstruction stretches from east of Avenue Road all the way to Bayview Avenue, encompassing the south side outer bridge and Yonge Street overpass.

Due to land constraints of the Valley and the need to accommodate the bridges, the adjacent interchange with Yonge Street is of a modified Parclo design instead of the typical Parclo A4 configuration used on most Ontario freeway junctions. The interchange is also one of the narrowler points of Highway 401's collector-express system, not just because of the bridges but also because of the suburbs east of Yonge Street (which forced the province to expropriate land in order to expand that segment of Highway 401). Only 12 through lanes cross Yonge Street, as the offramps and onramps default onto the main lanes instead of being additional de-acceleration and acceleration lanes.

At the foot of the bridges is the Earl Bales Park and Ski Centre in the north and Don Valley Golf Course to the south, both owned by the City of Toronto. An access road branches off from the westbound on ramp and travels downward to the valley below and ends in a cul-de-sac just south of the eastbound collector lanes.

The bridges can be clearly seen from Yonge Street looking northwest and north of York Mills Road and Wilson Avenue.