As many as 24 Montreal overpasses and tunnels are in critical condition, as the city makes plans to invest $87.8 million in infrastructure in the next few years.

Engineers who inspect city structures regularly, grade them on a scale of one to five, with five being good, and one being critical. Among the 24 deemed 'critical' are the Rockland overpass and the Angrignon overpasses.

Richard Deschamps, the Executive Committee member in charge of city infrastructure, said the critical structures are still safe but must be, and are, closely monitored to make sure they remain that way.

“It's only a vocabulary use. It doesn't mean that the structure is unsafe. So it's very different,” he assured Montrealers, explaining that 'critical' means several components of the structure aren’t functioning as they should.

Workd needs to be done to improve the structure in the short term, said Deschamps.

“If it would happen that it becomes unsafe, the engineers wouldn't hesitate to shut down a structure, or to restrain one lane or to decide any other interventions to ensure public security,” he said.

The 24 deemed 'critical' are an improvement over last year, when 27 structures were deemed to be in the worst possible shape, but worse than 2011 when 12 structures were listed as being in critical need of repair.

They are also first in line to be repaired.

"The site of the place where we have to intervene is inspected before action is taken and the engineer in charge decides what to do," said Deschamps. "Do we have to do additional appraisals? Do we have to put extra safety measures in place? Do we have to do emergency repairs or to close the structure?"

Montreal's road network is made up of 589 structures including bridges, tunnels, and overpasses.

The city says the majority of those structures are more than 40 years old, with 56 per cent built in the 1970s.

Montreal has earmarked $27 million next year on maintenance and repair to maintain the structures, which is in line with what was projected in 2012. Its ultimate objective is to invest $50 million annually into maintaining the road network.

Over the past two years many overpasses have come under rigorous examinations, which is why the number of critical and very poor structures increased.

Deschamps said that in the past two years many bridges and overpasses have been extensively repaired or torn down.

Overall the state of 18 overpasses and tunnels improved, while that of 40 structures deteriorated.

351 are in 'good' state, compared to 386 in 2012.