To amend title 23, United States Code, to establish additional requirements for certain transportation projects with estimated costs of $2,500,000,000 or more, and for other purposes.

Transportation Megaprojects Accountability and Oversight Act of 2018 This bill requires a recipient of assistance under National Highway System provisions for a megaproject (a project that has an estimated total cost of $2.5 billion or more), to submit to the Department of Transportation 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 benefits.