Highway-integrated photovoltaics (PV) offer a unique opportunity to decarbonize the transportation and power sectors simultaneously. However, no systematic assessment has yet evaluated their current development, performance, lessons learned, and barriers. This paper fills this gap by combining province-level field and correspondence surveys of highway PV projects in 28 provinces with a focus group workshop involving highway, energy and utility experts held in October 2024. Descriptive statistics reveal that typical highway PV project capacities range from 1 to 14 MW, annual electricity generation centers around 7 GWh, and deployment concentrate in service areas and toll stations. The dominant grid-connection mode is “self-consumption with surplus feed-in”, while financing models vary from energy management contracts to equity-debt mixes. Median internal rates of return of 8% and payback periods of 13 years suggest moderate economic viability, contingent on supportive policies. Qualitative analysis highlights five barriers: regulatory ambiguity, institutional fragmentation, incomplete standards, specialized technical barriers, and market constraints. Overcoming these barriers will require dedicated policies, strengthened cross-sector coordination, unified standards, targeted technical innovation, and scalable financing mechanisms. The findings enrich the emerging literature on transport-energy integration and offer insights for countries planning to develop solarized highways.