Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

The latest information on the Coronavirus Disease 2019 (COVID-19) is available on

United States Department of Transportation United States Department of Transportation

Recently Completed Research Projects

From 2020 to 2021

From 2019 to 2020

From 2018 to 2019

From 2017 to 2018

From 2016 to 2017

From 2015 to 2016

From 2014 to 2015

From 2013 to 2014

Last updated: Monday, October 18, 2021