The average age of bridges and overpasses in Ontario has evolved irregularly since the early 1960s, reaching an all-time low of 21.8 years in 1993. Thereafter, more moderate investments raised the average to a record high of 24.5 years in 2004. The trend has reversed since and large investments in recent years brought the 2007 average to 24.1 years.
Yet, Ontario ranked third among provinces in terms of having oldest bridge infrastructure in 2007, after Quebec and Nova Scotia. Bridges and overpasses in Ontario accounted for 7% its public infrastructure stock in 2007. As a percentage of estimated useful life, Ontario rate was very close to the national average in most years. In 2007, the rates were 56% in Ontario compared to 57% nationally.