Class D refers to a category of vehicles that are designed for specific purposes, often related to commercial use. These vehicles typically include larger trucks and buses that require a special license to operate. Drivers must pass tests to ensure they can handle the size and weight of these vehicles safely on the road. In many regions, obtaining a Class D license involves both written and practical exams. This ensures that drivers are knowledgeable about road safety and regulations. Class D vehicles play a crucial role in transporting goods and people, making them essential for businesses and public transportation systems.