This study tests how a transit system can enhance substance abuse treatment outcomes and reduce provider-level treatment costs for substance abuse amidst the opioid crisis in Connecticut. Increasing access and retention in treatment services is critical to improving health outcomes and reducing substance abuse overdose deaths. Using a difference-in-differences method, the research project will test how treatment costs differ before and after a new transit line and/or a change in transit service schedules. With empirical evidence on how transit schedules and lines impact costs and health outcomes, researchers will leverage relationships with state, transit officials, and public health agencies to implement a systems alignment plan that sustains transit lines and schedules that pass closer to treatment providers offer transit spurs to treatment providers, and/or encourage treatment providers to relocate closer to existing transit routes. Researchers at the University of Connecticut will collaborate with an ongoing advisory panel made up of CT treatment providers, the CT Department of Transportation, CT Department of Public Health, and the Department of Mental Health and Substance Abuse. Findings will be moved in to action through the ongoing advisory panel to disseminate findings locally, regionally, and nationally.