GPS traces are not suited for direct upload to OSM as already mentioned by SomeoneElse. They usually contain too many points and simply converting them to a way doesn't create the required junctions/connections with surrounding ways. You should always create the way by yourself, adding points where necessary and omitting points when the way is just straight.
The Wiki has multiple pages about processing GPS traces:
- [uploading a GPX file][1]: this is not necessary for adding ways in OSM, but might help other people later when editing those ways again
- using a GPX file:
- for file with [Potlatch][2]: [loading previously uploaded traces][3] and [creating points and ways][4]
- for using a GPX file with [JOSM][5]: [loading a local trace][6] and [adding a way][7]
[1]: http://wiki.openstreetmap.org/wiki/Upload
[2]: http://wiki.openstreetmap.org/wiki/Potlatch_2
[3]: http://wiki.openstreetmap.org/wiki/Potlatch_2/Primer#GPS_data_.2F_My_tracks
[4]: http://wiki.openstreetmap.org/wiki/Potlatch_2/Primer#Creating_Features
[5]: http://wiki.openstreetmap.org/wiki/Josm
[6]: http://wiki.openstreetmap.org/wiki/JOSM/Guide#Load_a_local_GPX_file
[7]: http://wiki.openstreetmap.org/wiki/JOSM/Basic_editing#Adding_a_way
