Options to increase the gross weight of heavy trucks are being addressed through studies
on size and weight in the United States. These options would require more axles per truck. If
the truck configuration and equipment are not tightly controlled by regulation, many of these
axles would be liftable axles, and the trucks would be similar to those used already in central
and Atlantic Canada. Allowing heavy trucks to use liftable axles, where the axle load is
controlled by the driver, may lead to axle weight compliance problems and, eventually, result …

The provinces of central and eastern Canada have tolerated the use of liftable axles on
heavy trucks for many years, and about one quarter to one third of all heavy trucks, a
majority of the truck population that hauls the heaviest loads, are so equipped. These trucks
have been configured for the most part simply by means of a bridge formula, and their
performance as vehicles has been compromised to generate the highest possible gross
weight. This paper presents some theoretical highway impacts of typical heavy trucks that …