Final answer:
Soldiers are ordered to "route step" (walk out of step) across a bridge to reduce resonance, enhance stability, and ensure the safety of the bridge.
Step-by-step explanation:
Soldiers are ordered to "route step" (walk out of step) across a bridge to reduce resonance.
When soldiers march in step, their rhythmic footsteps can create a resonance frequency that matches the natural frequency of the bridge, leading to excessive vibrations. This can potentially cause the bridge to sway dangerously or even collapse. By walking out of step, soldiers disrupt the resonance and prevent the amplification of vibrations, thus enhancing stability and ensuring the safety of the bridge.