What does a rearward amplification value of 3.5 for a triple-trailer combination mean?

AAMVA CDL Manual, Section 6.1.2 'Steer Gently,' p. 6-1 to 6-2, Figure 6.1

Longer combinations like triples amplify steering inputs toward the back of the rig, so a seemingly minor steering correction up front can become a severe swing at the rear. Knowing which configurations have the worst rearward amplification explains why extra caution is required with multi-trailer combinations.