Tunnel vision can lead to the downfall of a project because you may miss valuable information or indicators while focusing on a single task. I think the best way to avoid tunnel vision is to have an experienced project team that has open communication and are willing to voice their opinion when they think tunnel vision is occurring or if they feel attention should be guided elsewhere. It’s easy to fall victim to tunnel vision when you are working alone, but I feel that the team aspect of a project is the first line of defense against it, for instance having multiple team members weigh in on a project during the planning phase and sorting out tasks and breaking them down into simple subtasks.