This review was performed at the request of Washington State DOT (WSDOT) to assess its sustainability efforts. SSTI convened a panel of experts that included people who have led transformative initiatives as heads of state DOTs. The panel combined practical and academic thinking. The expert panel reviewed background materials on WSDOT’s efforts and then interviewed stakeholders with varying perspectives on WSDOT’s work, including WSDOT staff; personnel from other state, federal, and local entities; and representatives from the not-for-profit sector. Intended as a peer review rather than an audit, the expert panel members brought their knowledge of transportation policy and trends to bear in assessing where WSDOT has succeeded and how its sustainability efforts could be strengthened.