The Pankian Metaphor 3068

Not to mention freeze-thaw cycles. Roads without maintenance wear out all by themselves.. nary a truck in sight, as anyone who has ever owned a driveway can testify.

Having worked in the industry all my life, I can state that *all* axle loads are considered. In fact, the definition of "commercial vehicle" is based on axle weight, here in Ontario. The rate of wear on a pavement is proportional to the pounds per square inch of the load on that highway. Unless a car weighs nothing, or it's tires do not contact the road, then it wears on the roadbed Since the wear is somewhat exponential, the higher truck loads are particularly important, and road taxes (Trucks *do* pay road tax when they get their licences) are often based on axle loading.

The fact that "x" number of cars of a lower axle weight go over a particular spot is certainly considered at the design stage though.

Axle weights in the states tend to be much lower (by law) that here in Canada. The maximum weight for a truck here is 128,000 pounds. In the states, it is state governed, but the states I have designed truck scales for have all been under 80,000 pounds. Michigan, for example, was 78,000 last time I checked (several years ago).

Donald