Worked on the OpenTTD/OpenTTD repository to address a nuanced bug affecting road vehicle driving side consistency within the game engine. Focused on refining the NewGRF flag logic, the developer ensured that signals and road vehicles now correctly align with explicit left or right driving side settings, resolving mismatches between game configuration and NewGRF behavior. The solution involved updating the TTDPatchFlag evaluation and clarifying user-facing labels to enhance maintainability. Utilizing C++ and applying expertise in game engine development and localization, the work reduced edge-case bugs and improved compatibility across custom content, contributing to a more robust and predictable gameplay experience.