Alberta Highway 591

The Canadian province of Alberta has provincial highway network that was nearly 31,000 kilometres (19,000 mi) in length as of 2009, of which 24,851 kilometres (15,442 mi) were paved.

All of Alberta's provincial highways are maintained by Alberta Transportation (AT), a department of the Government of Alberta. The network includes two distinct series of highways. The "1 - 216" series of numbered provincial highways, formerly known as primary highways, makes up Alberta's core highway network. Highways within this series typically have the highest traffic volume and are mostly paved. The "500 - 986" series of numbered provincial highways provide more local access and include a higher proportion of gravel highways.

The province of Alberta abandoned its system of marking highways by different colours in 1926 in favour of a numbering system. By 1928, the year a gravel road stretched from Edmonton to the United States border, Alberta's provincial highway network comprised 2,310 km (1,440 mi).

Prior to 1973, the expanding provincial highway system in the province comprised one-digit and two-digit highways with some highway numbers having letter suffixes (e.g., Highway 1X, Highway 26A). In 1973, a second highway system emerged. They were numbered using three digits starting in the 500s and referred to as secondary roads, while the pre-existing highway system continued to be referred to as provincial highways. The following year, in 1974, the provincial highways were rebranded as primary highways, while the secondary roads were rebranded as secondary highways in 1990.

Secondary highways were abolished in 2000 with most of them becoming primary highways. The expanded primary highway system was organized into two subsets – the former primary highways were organized into the 1 - 216 series while the former secondaries were organized into the 500 - 986 series. The primary highway terminology was subsequently abandoned in 2010 in favour of referring to all highways as provincial highways instead while maintaining the two series established a decade earlier. Despite the changes in nomenclature in 2000 and 2010, the 1 - 216 series and the 500 - 986 series of highways are often still referred to as primary and secondary highways respectively.

Alberta’s 1 to 216 series of provincial highways are Alberta’s main highways. They are numbered from 1 to 100, with the exception of the ring roads around Calgary and Edmonton, which are numbered 201 and 216 respectively. The numbers applied to these highways are derived from compounding the assigned numbers of the core north-south and east-west highways that intersect with the rings roads. In Calgary, Highway 201 is derived from the north-south Highway 2 and the east-west Highway 1. In Edmonton, Highway 216 is derived from the same north-south Highway 2 and the east-west Highway 16.

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Wikipedia