Gardiner Expressway

The Frederick G. Gardiner Expressway, commonly known as the Gardiner Expressway or simply the Gardiner, is a partially at grade and elevated municipal expressway in Toronto, Ontario, Canada. Running close to the shore of Lake Ontario, it extends from the foot of the Don Valley Parkway (DVP) in the east, just past the mouth of the Don River, to the junction of Highway 427 and the Queen Elizabeth Way (QEW) in the west, for a total length of 18.0 kilometres (11.2 mi). East of Dufferin Street to just east of the Don River, the roadway is elevated for a length of 6.8 kilometres (4.2 mi), unofficially making it the longest bridge in Ontario, as it runs above Lake Shore Boulevard east of Spadina Avenue. The Gardiner Expressway is wholly owned and operated by the City of Toronto.

The Gardiner is named after the first chair of the now-defunct Metro Council, Frederick G. Gardiner. The six-lane section east of the Humber River was built in segments from 1955 until 1964 by the Metropolitan Toronto government with provincial highway funds, and upon completion the Gardiner also received the Highway 2 provincial route numbering until 1998. The ten-lane section west of the Humber was formerly the eastmost section of the QEW until downloaded to Metro Toronto in 1997.

The Gardiner has been described as "an out-of-date, crumbling and frequently traffic-jammed freeway". Particularly for the elevated section whose condition has deteriorated over the years, extensive repairs were carried out in the mid-1990s, coinciding with significant commercial and residential development in the vicinity. Due to its limited capacity and high maintenance, the Gardiner has been the subject of several proposals to demolish it or move it underground as part of downtown waterfront revitalization efforts. The section east of the Don River was demolished in 2001, while in 2018 the offramp to York/Bay/Yonge Streets was replaced by an offramp to Lower Simcoe Street, and the segment east of Jarvis Street to the Don River is to be realigned as of August 31, 2021.

In November 2023, the municipal and provincial governments announced a tentative deal which will see responsibility for the Gardiner Expressway and Don Valley Parkway transferred to the provincial government, with the two highways to be maintained as provincial highways.