divided highways in Alberta outside of urban areas. Interstate 15 becomes Highway 4 as it crosses the international border between Montana and Alberta into Coutts, the only border crossing between Montana and Alberta that is open 24 hours year-round. The highway curves north out of Coutts alongside the railway to a three-way intersection with Highway 501 which leads west to Del Bonita. The two highways continue concurrently to the north, briefly paralleling Milk River. The concurrency ends and Highway 501 splits to the east into the community of Milk River, becoming Railway Street, while Highway 4 continues north across the river to bypass the town. Highway 4 continues north to Warner, which it bypasses to the east; the original alignment of the highway was directly through the community. From Warner, Highway 36 splits to the north en route to Taber and Vauxhall. Highway 4 continues north-northwest to the Hamlet of New Dayton and an intersection with Highway 52 at Craddock, leading west to Raymond. Further north, Stirling Lake and the town of Stirling lie immediately west of Highway 4. New pavement was built east of Stirling to allow the divided highway to curve smoothly to the northeast, and a portion of the former two lane road remains. Just north of Stirling, Highway 61 splits to the east leading to Foremost. North of Stirling, the community of Wilson Siding lies at the intersection of Highway 4 and Highway 845. Highway 4 reaches Lethbridge and curves due west across the CPR tracks becoming 24 Avenue South. In Lethbridge, the highway turns north onto 43 Street as a major arterial road with a speed limit of . It intersects the major east-west arterial routes of 20 Avenue and South Parkside Drive in south Lethbridge before crossing the Canadian Pacific Railway tracks a final time, then ends at an intersection with Crowsnest Trail. With only four traffic lights, it provides an alternative to the busy Mayor Magrath Drive, the main north-south route in Lethbridge, which has a dozen sets of lights over the same distance. The section of 43 Street near 6 Avenue South is the busiest part of Highway 4, carrying over 19,000 vehicles per day in 2017. Between Lethbridge and Wilson Siding, traffic quickly decreases to less than 10,000 vehicles per day, and less than 5,000 vehicles per day for the remaining until Coutts. History Sunshine Trail Like many other main highways