B737-3000 CAPT STOPPED ABRUPTLY DURING TAXI TO GATE TO AVOID A VEHICLE XING IN FRONT OF HIM.

Narrative

I WAS PARKING AT GATE X. ANOTHER ACFT WAS ALSO PARKING AT GATE Y NEXT TO US. BOTH ACFT WERE UNDER MARSHALLER CTL. CONTRACTOR VAN WITH COMPANY LOGO ON ITS SIDE; PARTIAL PLATE #XXX CUT BEHIND THE PLANE AT GATE Y AND IN FRONT OF US AT GATE X. HE PASSED APPROX 20 FT IN FRONT OF US WHILE WE WERE MOVING FORWARD. I HAD TO STOP THE ACFT RATHER ABRUPTLY WHEN I SAW HIM COMING AT US FROM THE SIDE. HE NEVER MADE ANY INTENTION OF STOPPING OR YIELDING. OUR MAINT MAN DID NOT SEE HIM UNTIL HE PASSED IN FRONT OF US. PASSING IN FRONT OF US WAS NOT SAFE; BUT MORE SO THE PASS BEHIND THE OTHER ACFT WHO WAS PWRING FORWARD AT THE TIME. THE VAN COULD HAVE BEEN BLOWN OVER OR OUT OF CTL. I ATTEMPTED TO CALL THE CONTRACTOR BUT WAS UNSUCCESSFUL IN GETTING A NUMBER. I RPTED THE OCCURRENCE TO ZONE BUT THEY COULDN'T DO MUCH. I ATTEMPTED CONTACT WITH MR X; THE OPS PERSON I WAS TOLD WAS THE LIAISON FOR CONTRACTORS AT THE ARPT; AND HE WAS NOT IN. BASICALLY; THE CONTRACTORS ON THE FIELD MUST BE EDUCATED IN THEIR RESPONSIBILITIES WITH RESPECT TO ACFT MOVEMENT. THE RAMP AREAS ARE EXTREMELY CONGESTED. THE VAN DRIVER WAS NOT ONLY A HAZARD TO US BUT ALL THE RAMP PERSONNEL POSITIONED AROUND US READY TO SVC THE PLANES. THE GATE AREA WHERE WE WERE WAS VERY TIGHT. THAT SINGLE VAN CREATED A VERY HAZARDOUS SIT.