Regulatory Improvement and Transparency Act of 2017 Administrative Procedures Improvement Act of 2017 The bill revises the process that governs the way in which executive agencies may propose and issue regulations, including by establishing requirements that agencies must follow when proposing or issuing a major rule. A major rule is defined as one that is likely to cause an annual effect on the economy of $100 million or more, a major increase in costs or prices, or significant adverse effects on competition, employment, investment, productivity, innovation, public health and safety, or the environment. The Office of Information and Regulatory Affairs (OIRA) must provide guidance on, and oversight of, agencies' assessments of their proposed major rules. Pilot Retrospective Review Commission Act of 2017 The bill establishes in the legislative branch a Pilot Regulatory Review Commission to evaluate and provide recommendations for modifying, consolidating, or repealing certain regulations that impact the transportation sector. Plain Writing Act for Regulations Act of 2017 When issuing or revising regulations, executive agencies must use plain writing that is clear, concise, and well-organized if feasible. Office of Information and Regulatory Affairs Transparency Act of 2017 OIRA must ensure greater openness, accessibility, and accountability in the regulatory review process. Cost-Benefit Analysis Improvement Act of 2017 The General Services Administration must contract with the National Academy of Public Administration to publish a study on the costs and benefits associated with major rules.