You are pulling a set of triples and approach a curve with a posted advisory speed you have driven comfortably many times in a tractor-semitrailer. How should you treat that speed?

Explanation

Treat it as possibly too fast: a curve speed that feels fine in a straight truck or towing a single semitrailer can turn out to be too much once you are pulling a set of doubles or triples, so slow down further and steer gently. The reason is the same amplification that makes these combinations roll over more readily than a single trailer, which is why the manual's guidance for ramps, corners and curves is to go slowly rather than to lean on the posted figure. 49 CFR 383.115(c) names rollover in steady turns and yaw stability in steady turns as required knowledge, but it states no speed rule, so the practical guidance is attributed to the manual. The wrong options each rest on a false source of reassurance: treating a posted advisory speed as if it were validated for the longest and least stable combination on the road is exactly the assumption being warned against, extra unpowered axles do not add cornering stability to an articulated rig, and an empty or lightly loaded trailer is not the only condition in which a posted speed can be too fast.

Source: 49 CFR 383.115(c)