Transportation Megaprojects Accountability and Oversight Act This bill sets forth additional requirements for certain recipients of National Highway System assistance for a megaproject. (A megaproject is a project that has an estimated total cost of $2.5 billion or more.) Specifically, the bill requires a recipient of federal financial assistance for a megaproject to submit to the Department of Transportation (DOT) a comprehensive risk management plan that contains, among other things, a description of the process for identifying, quantifying, and monitoring the risks that might result in cost overruns, delays, reduced construction quality, or reduced megaproject benefits; establish a peer review group that consists of at least five individuals to give expert advice on the scientific, technical, and project management aspects of the megaproject; and publish specific information online, including the name, license number, and license type of each engineer supervising an aspect of the megaproject. DOT must make arrangements with the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine under which the board must convene a transportation megaprojects committee. These requirements apply to projects that are authorized for construction beginning at least one year after the bill's enactment.