Traumatic brain injury (TBI) is a leading cause of disability worldwide that can significantly impact the lives of those affected and their family/whānau. Recent evidence suggests that the number of people sustaining some types of TBI may be changing over time. Using proven methods, a new population-based study of TBI will confirm the current nature of TBI in New Zealand. This information will be compared to similar population data from 2010-2011 to determine the true extent of any changes in TBI over time. An additional focus will be on improving understanding of the limited access to initial TBI healthcare services that we observed in our prior research. Findings will help to make sure that TBI guidelines and services align with the true nature of TBI in New Zealand, and that services become more accessible and equitable for all New Zealanders to improve outcomes and reduce the national burden of TBI.