Crossing a railroad at grade is common in the US, and also quite dangerous. More than 2000 traffic incidents occurred at level crossings in 2016 alone, resulting in 265 fatalities(1). Those numbers could go down if drivers were aware of them. That requires accurate data about the location of at-grade crossings. Data that even the Federal Railroad Administration does not have. OpenStreetMap community member Mike Nice decided to do something about it. As a follow-on to the MapRoulette V1 rail crossings challenge (which was only partially completed), he created a MapRoulette V2 challenge for the community to look at the remaining 63,000 locations where a railroad crosses a road on OSM and 5300 locations where a railroad crosses a pedestrian path. Ten months later, this challenge is complete, and OSM now has what is likely to be the most accurate and up-to-date inventory of at-grade railroad crossings in existence!

1 (Data from FRA)[https://oli.org/about-us/news/collisions-casulties]