That Darn Cat

Frequency...
Frequency...
Frequency...
Not all frequencies are equal. Ear plugs do not protect the ears from all frequencies, high frequencies like the back up noises are dangerous because they confuse sensitive people and make drivers deaf. We have the technology for full viability and lower pitched noises, that don't travel so far and do so much damage to peoples hearing.
We have the science to fix this problem.

Deaf construction worker's 'demoralising' job hunt
https://www.bbc.com/news/uk-wales-40495692
Construction Workers and Hearing Loss - Going Deaf for a Living
https://www.healthyhearing.com/report/32255-Construction-workers-and-hearing