AN ACR BE02 FLC; WHILE ATTEMPTING TO EXIT GRR ARPT RWY 8R AT TXWY A4; EXITS THE RWY INTO THE SNOW. ACFT HAD TO BE EVACED. AFTER DISCUSSION WITH TWR; PLT IS ADVISED OTHER SIMILAR INCIDENTS HAVE OCCURRED AT THAT SITE.

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AFTER MAKING A NORMAL APCH AND LNDG ON RWY 8R AT GRAND RAPIDS; MI; I (PF) BROUGHT THE ACFT TO A FULL STOP BECAUSE VISIBILITY WAS REDUCED DUE TO BLOWING SNOW AND NIGHTTIME CONDITIONS. WE WERE TOLD TO EXIT AT FIRST AVAILABLE L. CAPT WAS LOOKING FOR REVERSE HIGH SPD TXWY A4. HE TOLD ME TO MOVE PROPS OUT OF BETA RANGE INTO ALPHA RANGE TO INCREASE VISIBILITY DUE TO SNOW BEING THROWN FORWARD. HE AND I SPOTTED A TXWY SIGN OFF L SIDE; BUT COULD NOT VERIFY IF THAT WAS TXWY A4 BECAUSE WE WERE ALREADY PAST THE FORWARD PART OF THE SIGN. ALL SURFACES WERE COVERED WITH A LAYER OF SNOW. NO MARKINGS ON THE RWY WERE VISIBLE; NO LEAD LINES; NO CTR LINES. HOWEVER; I SPOTTED A FLUSH MOUNTED RWY LIGHT AND TOLD THE CAPT THAT WAS PROBABLY OUR TURNOFF. BASED ON THAT INFO; WE MUTUALLY AGREED THIS MUST BE OUR TURNOFF BASED ON THE FLUSH MOUNTED LIGHT. WE SOON REALIZED THIS WAS NOT THE CASE. ABOUT 12 FT OFF THE RWY; I TRIED TO TURN THE PLANE OUT OF THE SNOW; BUT IT WAS NOW STUCK. CAPT CALLED THE TWR AND SHUT DOWN THE ACFT. I BRIEFED THE PAX ON OUR SIT. THERE WAS NO DAMAGE TO THE ACFT OR ARPT PROPERTY. IN RETROSPECT; I LEARNED THE BEST THING TO DO WOULD HAVE BEEN TO CALL THE TWR AND ASK FOR DIRECTIONS; THOUGH THE TWR PERSONNEL LATER SAID THERE HAD BEEN SEVERAL INSTANCES OF ACFT DOING EXACTLY WHAT WE DID AT SAME INTXN. IT IS POORLY MARKED AND THE LIGHTING MAKES IT QUITE CONFUSING IN A LOW VISIBILITY SIT.