The project was aimed at developing and demonstrating the application of a low-cost, environmentally-safe, polymer-based coating system for the corrosion protection of structural steel in highway facilities. A promising π-conjugated polymer, which was also an intrinsically conducting polymer (ICP), was developed and incorporated in the primer layer of the proposed two-layer coating system. The ICP-based primer demonstrated three major anti-corrosion mechanisms: (i) ennobling substrate surface, (ii) reducing coating delamination, and (iii) smart self-healing initiated corrosion. The two-layer coating system was made by coating the primer with a robust polyurethane layer and subjected to ASTM tests B117 (Salt Spray Test), D5894 (Cyclic Salt Fog and UV Exposure Test), and D4541 (Pull-Off Strength of Coatings) to evaluate its overall anti-corrosion and adhesion capabilities under accelerated corrosion conditions. Results indicated that this two-layer system possessed long-term durability, was able to provide long-term corrosion protection to steel substrate, and had strong long-term adhesion to the substrate steel surface. Two best-performing coating systems, each with an ICP-based primer layer, were then selected for field evaluation. Two field sites were selected for evaluating the performance of the selected coatings. Coated steel panels were exposed to the field corrosive conditions on a wooden stand at a 45° angle with respect to the ground surface. After 12 months of testing at both field sites, samples with polyurethane topcoat began to lose the original gloss and color while those with epoxy topcoat continued losing their surface luster. Rust material started to accumulate along the scribe marks on all treated and control samples at both sites. Based on blistering and rusting at the scribe marks and the pull-off strength measured before and after the 12-month field testing, the coating system including an ICP-based primer (made by mixing ICP in a regular epoxy matrix) and a polyurethane topcoat continued showing anti-corrosion performance comparable to that of the system with a zinc-rich primer and a polyurethane topcoat.