In the nation of Partoria, large trucks currently account for 6 percent of miles driven on Partoria' s roads but are involved in 12 percent of all highway fatalities. The very largest trucks-those with three trailers-had less than a third of the accident rate of single- and double-trailer trucks. Clearly, ttherefore, one way for Partoria to reduce highway deaths would be to require shippers to increase their use of triple-trailer trucks.
In Partoria, the maximum legal payload of a triple-trailer truck is less than three times the maximum legal payload of the largest of the single-trailer trucks most seriously weakens the argument.