Deerfoot Trail is a freeway segment of Highway 2 in Calgary, Alberta, Canada. It stretches the entire length of the city from south to north and links suburbs to downtown via Memorial Drive and 17 Avenue SE. The freeway begins south of Calgary where it splits from Macleod Trail, crosses the Bow River into city limits, and reaches the Stoney Trail ring road. Crisscrossing twice more with the river, it intersects Glenmore Trail and Memorial Drive; the former is a major east–west expressway while the latter is a freeway spur into downtown. In north Calgary, it crosses Highway 1 and passes Calgary International Airport before ending at a second interchange with Stoney Trail. Highway 2 becomes the Queen Elizabeth II Highway as it continues north into Rocky View County towards Edmonton. Originally called Blackfoot Trail Freeway upon the opening of the first section in 1971, it was renamed in 1974 to honour Deerfoot, a late-19th-century Siksika Nation (Blackfoot) long-distance runner known for his exceptional speed. Subsequent sections opened in 1975, 1980, 1982 and 2003. Deerfoot was not entirely a freeway until 2005 when the final of four at-grade intersections in southeast Calgary was converted to an interchange. Well known for its frequent rush hour congestion and collisions, traffic levels have steadily increased as Calgary's population has tripled to over 1.2 million since 1971. The mostly six-lane freeway is Alberta's busiest road with volume exceeding 173,000 vehicles per day between Highway 1 and Memorial Drive in 2019, more than twice that for which it was designed. The province of Alberta has been fiscally responsible for the road since 2000 but now seeks to offload maintenance and future improvement costs to the city of Calgary. The two parties remain at odds over who should operate the road in the long-term but completed a joint study in 2021 that offered long and short-term recommendations for improvement. A $478 million commitment to the freeway by Alberta was later reduced to $210 million. A public–private partnership project to improve the road includes widening, bridge twinning and interchange improvements; work is tentatively scheduled to begin in late 2022 to be completed by 2026. Route description Overview As a segment of Highway 2, Deerfoot Trail is a core route of the National Highway System and a key international corridor. It is also part of Calgary's Primary Goods Movement Network and is identified as a skeletal road in