Increasing emphasis is being placed on sustainability in the transportation sector. The City of El Paso, Texas, has been proactive in its approach and commitment to sustainability. The city's 2011 strategic plan lists various transportation- and community-oriented goals that provide direction for sustainable transportation initiatives. The new bus rapid transit system projects in the city are an important part of these and are the focus of the project described in this paper. This paper summarizes a recent exercise conducted to conceptualize the relevance of sustainability to transit corridors in El Paso and to identify performance measures that El Paso can implement. A set of 25 potential sustainability performance measures for rapid transit system corridors was identified. Selected performance measures from this set can be used to support specific corridor-level applications and to develop initiatives that can support the city at a strategic level to identify, track, and implement performance measures for sustainability and measure and communicate the value of investment in transit systems. The findings from this research will allow the city to communicate the value and benefit of bus rapid transit systems and provide tracking and decision-making tools that may be used to evaluate sustainability by the use of appropriate performance measures. The performance measures developed as part of this work will also have broader applicability to other cities, planning organizations, and transit agencies and can function as a performance measurement toolkit for practitioners looking to study sustainability in the context of transit systems.