The research aims to identify opportunities for investing in smart transport infrastructure as a driver of competitiveness in the digital economy of developing countries. To achieve this goal, the authors developed an econometric model based on international statistics for 2025, which examines the contribution of investments in smart transport infrastructure to the competitiveness of the digital economy in developing nations. The model’s theoretical significance lies in its ability to quantitatively characterize the patterns of competitiveness growth as investment activity in this sector increases. Based on the developed model, a new path for developing smart transport infrastructure in developing countries is proposed—private investment support for this infrastructure. The authors made projections up to 2030, making it possible to identify alternative scenarios of changes in the competitiveness of the digital economy in developing countries, depending on fluctuations in the volume of investments in smart transport infrastructure until 2030. The demonstrated scenarios revealed that a shortage of private investments in smart transport infrastructure could lead to a sharp decline in the competitiveness of the digital economy in developing countries. The authors argue that, depending on the scale of private investment in smart transport infrastructure, the growth of digital economy competitiveness in developing countries could range from 8.76 to 18.31% by 2030. These scenarios hold practical significance because they reduce uncertainty regarding the role of investment support for smart transport infrastructure, which, in turn, will help improve governmental policies for managing the competitiveness of the digital economy in developing countries.