TWO VORS; PSI AND PNT; HAVE NAME OF PONTIAC AND CAN BE CONFUSED BY PLTS IF ATC DOES NOT CLRLY IDENTIFY THE DESIRED FIX.

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ENROUTE WE RECEIVED A REROUTE WHILE CRUISING AT FL370; M.80. THE INITIAL POINT IN THE REROUTE WAS DIRECT 'PONTIAC.' MY FO LOOKED UP THE IDENTIFIER FOR PONTIAC; MI (PSI) AND ENTERED IT IN THE FMS. SHORTLY AFTER WE STARTED THE R TURN I NOTICED AN ACFT ON THE TCAS AT FL370 AND PICKED HIM UP VISUALLY CROSSING FROM L TO R IN FRONT OF US AT OUR ALTITUDE. I STOPPED THE R TURN AND CAME BACK L TO OUR ORIGINAL COURSE TO ENSURE WE WOULD PASS WELL BEHIND HIM. AT THE SAME TIME WE CONFIRMED THE IDENTIFIER FOR 'PONTIAC' WITH CHICAGO CENTER AND WERE TOLD PNT (PONTIAC; IL). MY FO ENTERED IT IN THE FMS AND WE PROCEEDED DIRECT; BASICALLY STRAIGHT AHEAD AND ONLY A FEW DEGS FROM OUR ORIGINAL COURSE BEFORE THE REROUTE. THESE MANEUVERS WERE ALL DONE ON AUTOPILOT. THE OTHER ACFT PASSED 5 NM IN FRONT OF US AND WOULD HAVE BEEN CLOSER HAD I NOT TURNED BACK TO THE L. THE TCAS RESULTED IN A TFC ADVISORY (TA) BUT NO RESOLUTION ADVISORY (RA). ATC WAS CONCERNED; AS WAS I; WITH THE ABOVE EVENTS SO I ASKED FOR AND RECEIVED A TELEPHONE NUMBER SO I COULD CALL THEM AFTER LNDG. I DID SO AND LATER THAT EVENING WAS INFORMED NO PLT DEV RPT WOULD BE FILED WITH THE FAA. CAUSE: THREE REASONS: 1) THE CTLR DID NOT USE THE PHONETIC IDENTIFIER (PNT) IN THE REROUTE INSTRUCTIONS. 2) WE DID NOT REQUEST A PHONETIC IDENTIFIER; BUT SIMPLY LOOKED IT UP; AND STARTED A TURN TO THE WRONG 'PONTIAC.' 3) THE MAJOR REASON THIS EVENT OCCURRED IS BECAUSE THE DEPARTMENT OF TRANSPORTATION/FAA HAS ALLOWED TWO NAVAIDS (VORS) IN THE SAME REGION OF THE UNITED STATES (THE GREAT LAKES) TO HAVE THE SAME NAME (PONTIAC). THIS IS AN ACCIDENT WAITING TO HAPPEN! SUGGESTIONS: CHANGE THE NAME OF ONE OF THE 'PONTIAC' VORS LIKE WE RECENTLY CHANGED THE NAME OF LAS VEGAS; NM; TO FORT UNION SO IT WOULD NO LONGER BE CONFUSED WITH LAS VEGAS; NV. DO THIS IMMEDIATELY!