Definitively mark or warn of overhead lines or low clearances. When digging, call Dig Safe or whichever agency has jurisdiction. Continue to use caution even after underground lines are marked, since errors in marking are common. Be prepared to hand dig when it's getting close.

Use sawhorses, signs, barrier tapes, etc., to indicate obstructions. Take no chances.

7. Backing
Reverse motion on anything in this industry is fraught with peril. Backup alarms on construction machinery are basically cosmetic devices in terms of assuring a clear backside. As such, operators need to positively assure that no one or nothing is behind them. This is achieved by getting out and looking.

Always check the machine perimeter before moving. When vision is impaired, have a spotter (in high-visibility apparel) guide you.

Use wide angle mirrors. The new generation of machines is fitted with best viewable surface mirrors. Keep them clean and adjusted.