Greenhouse gas emissions caused by the embodied carbon of steel are one of the most significant ways in which steel is utilized in transportation infrastructure projects because the industry has one of the highest embodied carbon rates. This research constructs an end-to-end Green Steel Adoption Playbook for U.S. state Departments of Transportation (DOTs) to define, size, and confirm low-carbon steel procurement with no safety, cost, or time risks to the organization. A mixed-methods strategy is adopted in the context of life-cycle assessment benchmarking on plant-specific Environmental Product Declarations (EPDs), exploratory data analysis, and visual analytics as filters of the data quality, principal component analysis diagnostics, and correlation-based feature selection, to determine transparent procurement requirements. A multi-criteria decision analysis (MCDA) model combines cost, carbon performance, and disclosure risk, and the simulations rank winner patterns, greenhouse gas reductions, cost premiums, and supply coverage at 10% to 30% weighting to carbon. Practical feasibility and administrative effects are bolstered by semi-structured DOT officials, fabricators, and mills. Findings demonstrate that dramatic short-term CO2 emissions cuts (for up to 40%) could be obtained at less than 5% cost premiums, CFS-selected features delivered resilient and explanatory scoring, and PCA could be employed to validate levels of robustness. Traceability of more than 90 percent was realized through a verification protocol that involved post-award audits and cross-checking mill-test reports. The playbook provides DOTs with practical recommendations, such as defining functional units, procurement scoring functions, verification procedures, and implementation plans, to trigger market indicators on green steel, adhere to Buy America/Buy Clean strategies, as well as infrastructural decarbonization. The framework is scalable, and it allows constant optimization.