THE INCIDENT TRANSPORT AIRPLANE COLLIDED WITH ANOTHER PARKED TRANSPORT AIRPLANE WHILE TAXIING AWAY FROM A GATE AT THE START OF A REVENUE FLIGHT. BOTH AIRPLANES SUSTAINED MINOR DAMAGE. THE PILOT STOPPED THE AIRPLANE AND SHUT IT DOWN. THE PASSENGERS AND CREW DEPLANED USING THE NORMAL CABIN EXITS. THE INVESTIGATION REVEALED THAT SIGNALMEN AND WINGWALKERS WERE ROUTINELY GROUND GUIDING AIRCRAFT AT THAT PARKING LOCATION TO A PARKING SPOT THAT WAS DISPLACED TO THE LEFT OF THE PAINTED TAXI GUIDE STRIPES. THIS PRACTICE ALLOWES THE TAIL OF A DEPARTING AIRPLANE TO TRANSCRIBE AN ARC WHICH PASSES THROUGH AN ADJACENT DEDICATED PARKING SPACE AS IT TURNES AWAY FROM THE GATE. WHEN THIS SPACE IS OCCUPIED BY A LONGER AIRPLANE THERE IS INSUFFICIENT CLEARANCE TO ALLOW THE TAIL SURFACES OF THE TWO AIRCRAFT TO CLEAR EACH OTHER. ACCORDING TO RAMP PERSONNEL AN EMERGENCY STOP HAND SIGNAL WAS ISSUED BY THE WINGWALKER BUT WAS NOT RECOGNIZED IN TIME TO STOP THE INCIDENT.