I started correcting some of the map data regarding separate lanes ans oneways. I did a part of Main Street east of Ames, where the old map data was topologically incorrect, particularly the connection between Main and Broadway. I plan to slowly move on from there to the east and north. Anybody living in the area, please take a look at the OSM data and let me know what you think.

I am spending way too much time on this! After some encouragement by other OSM contributors, I started to verify the map data of the area I live/work in. While doing so, it occured to me that there must be some way to map/tag something like an underpass to make the renderer draw it correctly. To my surprise, I did not find much on this topic in my favorite wiki pages (Map features and Proposed features) and a quick search revealed only some old email discussion (see http://lists.openstreetmap.org/pipermail/talk/2006-January/002215.html). I guess I somehow have to find out if the elevated tag mentioned there is really the way to go or if there is some other way to map multiple road levels.

I discovered OSM a few days ago and decided to start contributing on my own. For now I am concentrating on the place I live, Cambridge, MA, USA. I am surprised how good the street coverage already is - apparently mostly imported from public sources. I am mainly adding some amenities such as shops, cafe's, and other features, and add some detail such as data on bike lanes. Furthermore, I am fixing up a few obvious errors.