It is well established that organized systems of trauma care improve mortality and reduce complications after injury. The distribution of trauma centers within a system, including the number, level, and location of these centers, is an essential determinant of efficient function. The necessity for thoughtful designation of trauma centers, based on the needs of the population served, has been a recognized fundamental of trauma system design since their beginnings in the 1970s. Yet, almost 50 years later, there is still no consensus about the process for such a needs analysis or metrics on which it should be based. In the early days, the need to develop these metrics was not acute; decisions around trauma center designation were rarely controversial. There were very few trauma centers outside of large public hospitals, and the mission of a Level I trauma center was often financially unsustainable. Between 1990 and 2005, trauma center closings far outnumbered new trauma center designations, with more than 300 closing their doors. But by the early 21 st century, this balance had shifted. The evident success of systems-based trauma care, along with changes in healthcare economics, created an environment in which becoming a trauma center was highly desirable from the hospital perspective, and the number of facilities seeking trauma center designation increased dramatically. Rather than a triumph of the free market, the unfettered designation of new trauma centers based solely on economic drivers has the potential to destabilize existing trauma systems. New centers often arise in more affluent areas rather than areas of highest need, and might be in direct competition with existing centers for patient volume and revenue. This can result in decreased access to trauma center resources for vulnerable populations, despite an increase in the number of trauma centers.