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.