Climate change and the rising cost of potholes

After a snowy winter paired with temperatures that kept the Rideau Canal Skatewayclosed for the first time ever, people in Ottawa are beginning to see signs of spring.

Rising temperatures also lead to crumbling roads that can resemble the surface of the moon. Driving your car feels like riding a mechanical bull.

Anyone who lives in Ottawa knows spring is better known as pothole season.

Fluctuating temperatures create a destructive cycleof expansion and contraction of brittle, frozen asphalt, andmore powerful rays of sunshine meltice that has, for weeks, concealed cavities in the road.

Ottawa has 6,000 kilometres of roadway, each one subject to the nearly 80 freeze-thaw cycles the city sees on averageeach year. Crews fillhundreds of thousands of potholes every spring,17,435 so farthis year, according to city staff.

Roads built without considering climate change

Some experts say the problem is only going to get worse.

"We builttheseroads many years ago without considering the climate change scenario," saidKamal Hossain, a professor of transportation engineering at Carleton University.

Crews have traditionally used a specific glue for asphalt but that material is highly sensitive to heat. As Ottawa experiences hotter temperatures, it softens the asphalt and ultimately weakens the road further, he said.

The City of Ottawais well aware of this. Staffproduced a comprehensive reportlast spring listing the many risks to cityinfrastructure and to people's health as the weather becomes warmer, wetter and stormier. High up on the list: Ottawa's roadways.

"Road materials are not rated for the extent and duration of the heat events projected," the city's report on climate change vulnerabilities states. Winter freeze-thaw events "are particularly damaging" toroads and sidewalks, it said, because they cause cracking, heaving, potholes and rutting.

Pothole price tag growing

Crews already fill hundreds of thousands of potholes every year, more than 1.1 million in totalsince 2018.As the cost of labour, materials and the expansion of Ottawa's road network grows, so too does the cost of repairs.

The city's budget for asphalt repairs and maintenancehas steadily climbed over the last five years, and that doesn't even include the more costly jobs where entire roads are repaved.

Road users absorb costs, too, especially those who hangonto older vehicles to save money, which are more prone to damage,said Julie Beunof the Canadian Automobile Association (CAA) division for northern and eastern Ontario.

Whether it's a blown tire or damaged (possibly dislodged) bumper, potholes can cost a vehicle owner up to $6,000 to repair.

"We've got like 34,000 kilometres of what we've deemed as poor or very poor roads in Ontario, and so somebody's going to come to grief no matter how they move," said Beun.

Solutions are too expensive, says city

The solution changing the way roads are built requires significant investment, Hossain explained.

Some jurisdictions, including Canada's three territories, use concrete to enhance the durability of roads, but it is more costly than laying down asphalt.

The U.S., whichhas a Federal Highway Administration, spends hundreds of millions of dollars each year on researching road construction and sustainability. That is "a very unfortunate part that it is missing in Canada," said Hossain.

For the City of Ottawa, the last 10 years has been a period of trial and error for road building.

In 2018, contracts to asphalt supplierswere cancelled after a 2017audit found the materials fell short of required standards for fixingroads and potholes.

The city continues to search for a fiscally responsible way to fix the issue in the long term, according toCoun. Tim Tierney, who chairs the city'stransportation committee.

Tierney, who has been on city council for more than 12years, recalled a time when crewstried using beet juice to improve road traction unsuccessfully.

There is no room in the budget for concrete, he said.

Still, he acknowledges the city alreadyspends a lot of time and money maintaining its roads. In 2019 Ottawa bought two Python 5000s $400,000 machines that automatically cleanpotholes, fillthem with asphalt, and tampthem down.

Tierney said there will be four Pythons as part of Ottawa's repair fleet as of late March.

"As industry and technology gets better, hopefully we'll have a better solution," Tierney said.