Demystifying the Science | Truck Damage

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Almost all of them, according to several studies and a professor of civil engineering at the École de technologie supérieure (ÉTS).

“Even though there are many more cars than trucks, the responsibility of trucks in the deterioration of the roadway is almost 100%, explains Alan Carter, from ÉTS. Even if, in some neighbourhoods, we can have as little as 1% of trucks in the total traffic, it is still significant.”

That’s because roadway damage increases very quickly with weight. A heavy-duty truck with the maximum permitted load of 9,000 kg on the front axle will cause 6,500 times more damage than an F-150 pickup with 1,000 kg per axle, according to Mr. Carter. He notes that articulated buses can also cause a lot of damage to the roadway, because they carry more passengers per axle than a regular bus.

It’s a bit like hitting a brick wall with a spoon, compared to hitting it with a club. With the spoon, nothing moves, whereas with the club, the wall is damaged or even collapses.

Even the American Trucking Association (ATA) admits that trucks cause far more damage than cars. In 2018, it released a study it commissioned to debunk a commonly cited figure that a truck causes 9,600 times more damage than a car. That study concluded that a truck actually causes 2,000 times more damage than a car.

If we take the extreme case of a residential street where trucks constitute only 0.1% of traffic, if we assume that trucks cause 6,500 times more damage than cars, the latter only cause 13% of the damage to the street.

There are about 30 times more cars than trucks among registered vehicles, but trucks account for about 9% of the mileage, according to the last study on the subject by Statistics Canada, published in 2010. Trucks over 15 tonnes accounted for 6% of the mileage.

Grants

Over the past two years, two studies have estimated the real cost of different means of transportation in Quebec City and Montreal. They assessed the cost to owners (purchase of a car or a bus pass, for example) and to society (degradation of roads, pollution, congestion, as well as subsidies for public transportation and bike paths, in particular).

Now, both studies assumed that a truck causes the same damage to the roadway as a car.

“We mainly used data from the Origin-Destination Survey [qui étudie les déplacements de la population] “, says Jean Dubé, from Laval University, author of the study on Quebec. “Truck transport is therefore excluded from the portrait. It therefore does not enter into the calculation that we have made.”

This omission should not change much the observation that the car costs society more than public transit, according to Mr. Dubé. This is because the majority of costs for society are caused by pollution, congestion and the land cost of roads. To calculate the land cost of roads, Mr. Dubé’s study compares Quebec’s current roads to a situation where each street or road would have only one lane, with no parking lanes, simply to access homes, businesses, offices and industries.

The mobility cost studies in Montreal and Quebec City are based on a methodology developed by Todd Litman, a British Columbia urban planner who did the math for Vancouver. “I don’t think trucks cause thousands of times more damage than cars,” says Litman, who heads the Victoria-based Transportation Policy Institute, an independent think tank. “And even if they did, the cost of building a road in the first place has to be attributed to cars, in proportion to their use of the road.”

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