The growing pollution from transportation into the environment has created an urgent need for active mitigation tools. Photocatalytic surface treatments for concrete pavements, such as TiO2-based surface treatments, offer a promising solution by continuously reducing pollutants using solar energy. While previous research has shown that TiO2 surface treatments on concrete can reduce CO2 concentrations through photoreduction, quantifying the CO2 reduction remains necessary to understand their full potential under realistic conditions. This study presents a novel estimation model trained on experimental data from concrete slabs exposed to different light intensities (0, 23, and 100 W/m2) and CO2 concentrations (6%, 12%, and 100%) to estimate CO2 reduction (CDR). Results showed that both higher CO2 concentrations and higher light irradiance levels led to greater CDR, with maximum reductions of 0.2 g/m2 per hour under 6% CO2, 1.6 g/m2 per hour under 12% CO2, and 79.2 g/m2 per hour under 100% CO2, at 100 W/m2 irradiance. Two models were developed: a linear model, assuming CDR increases linearly with light irradiance, and a conservative model, with CDR plateauing at 100 W/m2. Using real sunlight irradiance and traffic data, the model estimates an annual reduction of 5.8–6.8 kg/m2 with the conservative model, while up to 25.8 kg/m2 with the linear model. Scaling it to 100 km of road, the TiO2 surface treatment could remove up to 4.1 M kg of CO2 annually in cities like Phoenix and 3.7 M kg in Seattle, demonstrating the potential of this technology for large-scale carbon removal.