Carmacks will carry out the daily maintenance of the Deerfoot Trail.
The contract involves the maintenance of 46km of motorway for seven years starting in August, with an option for a three-year renewal. The total value is about CA$120m (£68m).
Tasks under the contract include winter maintenance as well as the upkeep of infrastructure - bridges, roads and drains - and equipment such as crash barriers, signs and lighting. Camacks will also look after green spaces along the road.
The Deerfoot Trail is a two- or four-lane dual carriageway extending from the north to the south of Calgary, a city with a population of over 1 million. The motorway was named in 1974 after Deerfoot, an exceptionally fast long-distance runner of the Siksika North American Indian Nation. It is part of the Canamex corridor, a transport route linking Canada to Mexico via the United States, and is the busiest urban motorway in Alberta, with daily traffic of over 170,000 vehicles.