Narrative:

The airport has intersecting runways 2/20 and 9/27. Taxiway C is just past the intersection runway 2/20 when landing on runway 27. Taxiway C is fairly close to runway 2/20. The runways are 100 ft and 150 ft wide, respectively.. I normally fly from an airport with a runway width of less than 50 ft. I was cleared to land on runway 27. As I was crossing the runway threshold, another airplane was cleared to taxi into position and hold. I successfully landed and was cleared for a right turn onto taxiway C. In my haste to clear the runway for the plane behind me, I accidentally turned onto runway 20. I remember making a sharp right turn (more than 90 degrees) onto what I thought was the taxiway. The sharp right turn seemed 'unusual' to me but I didn't really give it a second thought because the airport diagram showed that any right turn onto a taxiway from runway 27 would likely exceed 90 degrees. The controller then informed me that I was on a runway, but since that runway wasn't active it wasn't a serious problem. In summary, I think there were 3 contributing factors: 1) the distraction of the airplane waiting to take off. I was in a hurry to clear the runway when I shouldn't have been. 2) the timing of the taxi clearance. It just happened to occur when what turned out to be runway 2/20 was the most prominent piece of asphalt on my mind, the runway signs were located off or behind my wing tip where I was not looking for any signs, and the taxiway C sign was in front of me where I expected to see it. 3) perception issues caused by intersecting runways wider than I am used to. I would not have believed that it was possible to perform a 10-15 ft back-taxi and believe I was simply making a sharp turn. But, that appears to be what I did. If I had realized I was back-taxiing, at the very least, I would have wondered why the controller was sending me to a taxiway behind me when there were still others in front of me.

Google
 

Original NASA ASRS Text

Title: A PA28 PLT, AFTER LNDG AT HGR, EXITED THE RWY ONTO ANOTHER RWY INSTEAD OF ATC'S ASSIGNED TXWY.

Narrative: THE ARPT HAS INTERSECTING RWYS 2/20 AND 9/27. TXWY C IS JUST PAST THE INTERSECTION RWY 2/20 WHEN LNDG ON RWY 27. TXWY C IS FAIRLY CLOSE TO RWY 2/20. THE RWYS ARE 100 FT AND 150 FT WIDE, RESPECTIVELY.. I NORMALLY FLY FROM AN ARPT WITH A RWY WIDTH OF LESS THAN 50 FT. I WAS CLRED TO LAND ON RWY 27. AS I WAS XING THE RWY THRESHOLD, ANOTHER AIRPLANE WAS CLRED TO TAXI INTO POS AND HOLD. I SUCCESSFULLY LANDED AND WAS CLRED FOR A R TURN ONTO TXWY C. IN MY HASTE TO CLR THE RWY FOR THE PLANE BEHIND ME, I ACCIDENTALLY TURNED ONTO RWY 20. I REMEMBER MAKING A SHARP R TURN (MORE THAN 90 DEGS) ONTO WHAT I THOUGHT WAS THE TXWY. THE SHARP R TURN SEEMED 'UNUSUAL' TO ME BUT I DIDN'T REALLY GIVE IT A SECOND THOUGHT BECAUSE THE ARPT DIAGRAM SHOWED THAT ANY R TURN ONTO A TXWY FROM RWY 27 WOULD LIKELY EXCEED 90 DEGS. THE CTLR THEN INFORMED ME THAT I WAS ON A RWY, BUT SINCE THAT RWY WASN'T ACTIVE IT WASN'T A SERIOUS PROB. IN SUMMARY, I THINK THERE WERE 3 CONTRIBUTING FACTORS: 1) THE DISTR OF THE AIRPLANE WAITING TO TAKE OFF. I WAS IN A HURRY TO CLR THE RWY WHEN I SHOULDN'T HAVE BEEN. 2) THE TIMING OF THE TAXI CLRNC. IT JUST HAPPENED TO OCCUR WHEN WHAT TURNED OUT TO BE RWY 2/20 WAS THE MOST PROMINENT PIECE OF ASPHALT ON MY MIND, THE RWY SIGNS WERE LOCATED OFF OR BEHIND MY WING TIP WHERE I WAS NOT LOOKING FOR ANY SIGNS, AND THE TXWY C SIGN WAS IN FRONT OF ME WHERE I EXPECTED TO SEE IT. 3) PERCEPTION ISSUES CAUSED BY INTERSECTING RWYS WIDER THAN I AM USED TO. I WOULD NOT HAVE BELIEVED THAT IT WAS POSSIBLE TO PERFORM A 10-15 FT BACK-TAXI AND BELIEVE I WAS SIMPLY MAKING A SHARP TURN. BUT, THAT APPEARS TO BE WHAT I DID. IF I HAD REALIZED I WAS BACK-TAXIING, AT THE VERY LEAST, I WOULD HAVE WONDERED WHY THE CTLR WAS SENDING ME TO A TXWY BEHIND ME WHEN THERE WERE STILL OTHERS IN FRONT OF ME.

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.