OMG, talk about trying to solve a problem where none exists.

Maybe you should close your windows? Most construction noise is
transitory anyway -- eventually the job is finished and the heavy
equipment is moved somewhere else.

While I'll admit the beeping requirement is largely a CYA measure,
your proposals make little sense. Cameras? "Object sensors?"
(Would have to be optical or radar.) Your proposals are at least
a couple of orders of magnitude more expensive and more complicated
then a simple beeper wired into the backup lights. And when they
fail -- and they will -- then there is a liability issue as well.

Your musings on this illustrate the worst about people who think
every problem or issue can be solved with technology.