The City of Toronto is proposing an infusion of $505 million for repairs to the aging Gardiner Expressway over the next 10 years, even as the cost of maintaining local roads and sidewalks goes up dramatically in that time frame.

The spending on "state of good repair" for the elevated highway that runs just north of the Toronto shoreline is laid out in the proposed capital budget for the city for the years 2013-2022. If approved, that move would cut the capital repair backlog on the expressway in 10 years to $121.1 million from the current $626.4 million backlog, representing a reduction of 81 per cent.

But the repair backlog for major roads would go to $216.5 million from $67.2 million in that period, an increase of 222 per cent. The repair backlog for local roads would go to $281.4 million from $132.3 million, an increase of 113 per cent.

The repair backlog for sidewalks, meanwhile, would go up to $26.6 million from $14.2 million, an increase of 87 per cent.

"The increase in backlog for these asset categories results from the city's aging infrastructure, more than half of the almost 4,500 lane-kilometres of arterial roads in the city were constructed during the period between the early 1960s and late 1970s," city staff said in budget documents.

The transportation department is currently "addressing infrastructure needs for those streets built in the 1950s."

The proposal for increased spending on the Gardiner comes after an independent study surfaced in October that found the highway’s deteriorating concrete poses a significant safety hazard.

Several chunks of concrete have fallen from the Gardiner's underbelly in the past year, forcing inspections and closures. No one was hurt in those incidents.

The proposed budget for the transportation department has to be approved by council before it can be implemented.