Bridges and overpasses in Alberta, which accounted for 9% of total public infrastructure stock in 2007, were young relative to the Canadian average. However, the average age of this asset has been on a steady increase since 1989 when it stood at 18.9 years. Investments in this asset from 1990 to 2006 had not been large enough to stop the ageing trend. As a result, the average age of bridges in the province increased to 23.0 years by 2006 and stayed at the same age in 2007.
As a percentage of estimated useful life, investment in this infrastructure in Alberta was consistently greater than the national average up to 1980. Thereafter, it was consistently below the national average. By 2007, bridges and overpasses in Alberta had reached 53% of their estimated life, compared with 57% nationally.