How can you avoid creating noise?

The selected combination of answers is correct because both actions directly contribute to noise reduction in traffic settings.

1. Filling empty compressed air tanks from a stationary facility minimizes operational noise because it avoids unnecessary noise from transport or handling.
2. Replacing worn-out side latches helps to prevent rattling or clanking noises while driving, contributing to a quieter environment.

These actions align with German traffic regulations that emphasize the importance of minimizing noise pollution for the benefit of public well-being and environmental considerations. Allowing the engine to idle, as mentioned in option 3, actually creates more noise and should be avoided during longer waiting times as stipulated by regulations aimed at reducing sound emissions. Therefore, the correct combination focuses on proactive maintenance and strategic operational practices to ensure a quieter traffic experience.