United States Transportation Command Infrastructure Assessment Act of 2018 This bill requires the United States Transportation Command, in coordination with the Department of Transportation (DOT), to make available to congressional Appropriations, Armed Services, and Transportation committees a description and assessment of the condition of the defense transportation sector functions, systems, assets, and dependencies as they relate to supporting Department of Defense operational capabilities and assets, including any related Transportation Engineering Agency Infrastructure Assessments. In coordination with DOT, the Command shall identify and submit to those committees consolidated and prioritized resource requirements for transportation infrastructure at the same time the President submits to Congress the budget for the next fiscal year.