Narrative:

After landing on runway 12 at bozeman, I was looking for taxiway east for exit from runway. Once I took the r-hand turn, I discovered I was on runway 21. FSS said that runway not stressed for air carrier aircraft, however, no signage was present to direct me to properly stressed taxiing surfaces. Air carrier has confusing note in air carrier 10-7A page, and signage coupled with width of runway 3/21 (looking like taxiway from perpendicular perspective) makes this runway easily mistaken for a taxiway.

Google
 

Original NASA ASRS Text

Title: THE FLC TAXIED B727 ON RWY 3-21 WHICH MAY EXCEED THE RWY WT BEARING CAPACITY AGREED TO BY THE ACR.

Narrative: AFTER LNDG ON RWY 12 AT BOZEMAN, I WAS LOOKING FOR TXWY E FOR EXIT FROM RWY. ONCE I TOOK THE R-HAND TURN, I DISCOVERED I WAS ON RWY 21. FSS SAID THAT RWY NOT STRESSED FOR ACR ACFT, HOWEVER, NO SIGNAGE WAS PRESENT TO DIRECT ME TO PROPERLY STRESSED TAXIING SURFACES. ACR HAS CONFUSING NOTE IN ACR 10-7A PAGE, AND SIGNAGE COUPLED WITH WIDTH OF RWY 3/21 (LOOKING LIKE TXWY FROM PERPENDICULAR PERSPECTIVE) MAKES THIS RWY EASILY MISTAKEN FOR A TXWY.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.