Blocked Rail Crossings Safety Improvement Act of 2021 This bill addresses safety and congestion along railroad right-of-way and highway-rail grade crossings. For example, the bill directs the Department of Transportation (DOT) to provide grants to (1) assist state, local, and tribal governments in funding the cost of highway-rail grade crossing separation projects; and (2) help nonprofit organizations carry out public information and education programs to help prevent and reduce rail-related pedestrian, motor vehicle, and other incidents, injuries, and fatalities, and to improve awareness along railroad right-of-way and at highway-rail grade crossings. Additionally, the bill prohibits railroad carriers from obstructing travel at public highway-rail crossings for more than 10 minutes, except under limited circumstances (e.g., safety issues). Further, DOT must (1) establish a national blocked crossings database for the public to report blocked crossing incidents; (2) conduct a comprehensive review of the national highway-rail crossing inventory; and (3) revise its regulations, guidance, or other relevant agency documents to include the number of suicides on a railroad crossing or railroad right-of-way in the total number of rail fatalities it reports each year.