The main and most complex superstructure module of heavy-duty and heavy commercial vehicles is the driver-passenger cabin. While cabin design and production; It must be safe, light, rigid, ergonomic, modular, suitable for lean production, user-friendly and serviceable. But the most important of these criteria is the life safety of the crew in the cab. In this context, the cabin strength must be at a very high level. To determine the cabin strength, it is subjected to the R29 - Cabin strength test within the ECE regulations. Thanks to this test, it is possible to see the skeletal strength and behavior of the cabin in the event of an accident or collision. According to this test, the life safety of the crew inside the cabin must be prioritized, and the necessary designs and production must be carried out to ensure that the cabin suffers as little damage as possible in the event of an accident. In this way, it is aimed to maximize the security (safe area) inside the cabin by providing cabin rigidity. This scope of work; The objectives of lighter weight, shorter and easier production, assembly and disassembly, lower production costs, less labor and equipment or consumable expenses have been achieved. Additionally, in this study, the seat configuration in the cabin was increased from 1+4 to 1+5 and a crash test was performed by including another door option.