WASHINGTON, D.C. – Dr. David Luskin thinks permit fees for heavy trucks should be based on a calculation about how axle loads affect pavement costs.

Luskin is from the University of Texas in Austin and was speaking at a meeting of the Transportation Research Board in Washington, D.C. last January.

This isn’t a new idea, although it’s surprising how few states or provinces have ever tried to calculate fees on the basis of pavement wear.

The only jurisdiction in Canada to do it is Saskatchewan.

In the U.S, while a number of states make a rough calculation every few years to see if total truck taxes like fuel and registration are equal to the costs trucks put on the roads, few states actually have a precise relationship between permit fees and pavement costs.

The exception is Oregon where detailed road costing work is done to set the level of fees for all its permit trucks above 80,000 lbs.

Oregon is the only state that has a fee schedule that increases with truck weight – the heavier the truck, the higher the fee – but also declines with the number of axles – the more axles for a given weight, the less impact on pavements.

There are a few other states – Minnesota is an example – where a calculation of pavement costs is used to set permit fees.

Texas has a special permit, called a ‘2060 permit,’ that allows trucks to operate at five per cent over the gross weight limit of 80,000 lbs and 10 per cent over axle weights.

Permit fees vary from $205 to $2,080 annually, depending on how many counties a trucker wants to operate in.

According to Luskin, the average fee paid is only $238 as most of the truckers applying for these permits are local operations – things like gravel trucks or other trucks used in the construction business.

The great advantage of a 2060 permit is that it allows trucks at 84,000 lbs to operate on rural roads that were only built with thin pavements and minimal-strength bridges.

Trucks without permits are limited to 58,420 lbs on these roads.

So a 2060 permit allows 25,000 lbs more payload on these rural roads and 4,000 lbs more on the Interstate and other high-class highways. Not a bad deal for an average fee of $238.

Here’s the problem.

According to Luskin, pavement costs on low-class, rural roads go from $0.38 per mile for a five-axle tractor-semitrailer at 58,420 lbs to an incredible $2 per mile when that same truck operates at 84,000 lbs.

The average fee of $238 doesn’t come close to compensating the government for the extra pavement costs.

On Interstates and other major highways, pavement costs for a five-axle tractor-semi-trailer go from $0.07 per mile at 80,000 lbs to $0.09 per mile at 84,000 lbs.

The difference is that, on thin pavements, one heavy axle has a big impact whereas on a high-class highway, the impact from one axle load is relatively small.

Hence, the big difference in pavement costs per mile.

But, whether on a low-class road or a highway, Luskin’s point is that these pavement costs are higher than the average annual fee of $238.

Pavements in Canada tend to be built stronger than pavements with comparable traffic loads in the U.S.. Primarily because they have to withstand deep freeze-thaw cycles.

In Ontario, for example, the Ministry of Transportation has calculated that an 80,000 lb truck only has a pavement cost of about $0.0015 per kilometre on highways like the 401.

That’s 15 one-hundredths of a penny. It is also $0.0015 per mile in U.S. funds, a considerably smaller number than Luskin’s $0.07 per mile on a Texas freeway.

But the same point that Luskin makes about pavements in Texas holds true in Ontario.

On lower-class roads, where pavements are thinner, pavement costs per kilometre increase in Ontario. According to the Ministry’s numbers, an 80,000 lb five-axle tractor-semi-trailer on a minor arterial street has a pavement cost of about $0.0238 – 16 times higher than on the 401.

On the lowest class roads in Ontario, truck pavement costs are even higher. But, and whatever the difference in pavement costs between Canada and the U.S., or between high-class highways and low volume minor rural roads, there are few states or provinces that actually attempt to calculate these costs when setting permit fees.

Saskatchewan is the only province to do this in Canada and it makes a specific calculation for trucks over normal gross weight limits for each permit holder under its Transportation Partnership Agreements.

In fact, other than some logging trucks in Alberta and British Columbia, Saskatchewan is the only province to allow permit trucking for divisible loads above the ordinary gross weight limit.

The long combination trucks – longer than 25 metres – seen in all three Prairie provinces and in Quebec are permit trucks hauling divisible loads but, in these cases, axle and gross weight limits are the same as for other trucks so the issue of extra pavement costs doesn’t arise.