I got Rhythm

It seems that whenever there is construction happening somewhere, that the slowly repeated “beep - beep - beep - beep” of a truck backing up never stops. Why is this? Do construction workers have something against other gears? Do they drive the vehicle around backwards the entire time that it is on the site? Is it something more complicated and calculated? Are they trying to distract surrounding people from the careless accidents and chaos that may actually exist within the construction site?

A) Did you hear that explosion?

B) No, that was just the truck backing up

A) Oh, ok. Nevermind.