For enhancing the charging infrastructure network coverage in populated areas, photovoltaic pavement (PVP) has been considered an innovative option that caters to distributed power generation and electric vehicles (EVs) charging in motion. However, the promotion of PVP has not yet served its intended purpose. This paper develops a gross net present value (GNPV) model to investigate the optimal timing to invest in PVP under stochastic electricity prices and time-dependent investment costs. Based on the photovoltaic highway project in Shandong, China, our numerical results reveal that the volatility of electricity prices, construction investment costs, and solar panels’ energy conversion efficiency significantly restricts the diffusion of PVP, resulting in the current dilemma of PVP adoption. However, the rapid decline in investment costs and the rapid increase in the number of EVs are not always effective in accelerating the PVP investment process, especially in some high electricity price regions, such as the southern areas of China. The findings of this paper will provide theoretical support and decision-making recommendations for the management evaluation of PVP projects, the optimization of charging facility networks, and the formulation of EV incentive measures.