Transportation Security Transparency Improvement Act This bill addresses policies of the Transportation Security Administration (TSA) related to sensitive security information and international aviation security. Among other requirements, the TSA must ensure clear and consistent designation of Sensitive Security Information , including reasonable security justifications for such designation; develop and implement a schedule to regularly review and update TSA Sensitive Security Information Identification guidelines; conduct outreach to relevant stakeholders (e.g., air carriers, airport operators, and state and local law enforcement) that regularly are granted access to Sensitive Security Information to raise awareness of the TSA's policies and guidelines governing the designation and use of Sensitive Security Information; and develop and implement guidelines with respect to last point of departure airports to conduct engagement with foreign partners on the implementation of security directives and emergency amendments.