Answer: Horizontal Directional Drilling (HDD) is a trenchless construction method used to install underground pipes, conduits, and cables without creating an open trench. It involves a surface-launched drilling rig that creates a bore path at a shallow curve. This technique is preferred because it significantly reduces environmental disruption, minimizes traffic interruptions, and allows for the installation of cables under obstacles like roads, rivers, and existing infrastructure. It is a faster, more cost-effective, and safer alternative to traditional open-cut trenching, particularly in urban or environmentally sensitive areas.