MD80 TAXIING FOR DEP AT LGA FAILED TO HOLD AT ATC DIRECTED POINT; RESULTING IN A GAR.

Narrative

AFTER SWITCHING FROM LGA RAMP FREQ TO LGA GND; WE WERE TOLD TO; 'FOLLOW ACR Y TO RWY 4; HOLD SHORT AT ILS HOLD LINE;' WHICH I REPEATED TO THE CTLR AND RECORDED ON MY YOKE NOTE. NORMALLY; I READ THE CLRNC TO THE CAPT AGAIN. I DON'T RECALL IF I DID SO THIS TIME. AS WE APCHED THE ILS HOLD LINE I STATED; 'I THINK WE'RE SUPPOSED TO HOLD SHORT HERE.' WE STOPPED APPROX 1 METER OR SO PAST THE LINE. I ADVISED TWR THAT WE HAD DONE SO AND THE CTLR SURPRISED BOTH OF US WITH AN IMMEDIATE GAR CALL FOR THE ACR Z; B757; ON FINAL TO RWY 4. THE CAUSE OF THIS GAR APPEARS TO BE OUR CREW'S FAILURE TO COMPLY WITH THE LGA GND CTLR'S CLRNC. CONTRIBUTING FACTORS: NEARLY ALL PLTS WILL EQUATE THE ILS HOLD LINE WITH POOR WX CONDITIONS. WX CONDITIONS AT LGA WERE GOOD WITH 10 SM VISIBILITY AND OVCST AT 20000 FT. THIS CREATES A 'LOGIC DISCONNECT' AND AN INCREASED LIKELIHOOD OF FORGETTING THIS INSTRUCTION; OR NOT ACTUALLY HEARING OR UNDERSTANDING IT IN THE FIRST PLACE. LGA GND SHOULD CONSIDER RESTATING THEIR SCRIPT TO READ 'HOLD SHORT AT THE ILS HOLD LINE TO CLR LNDG TFC.' PLTS FREQUENTLY RECEIVE THE SAME CLRNC AS THE ACFT IN FRONT OF THEM. THEREFORE; PLTS LEARN TO EXPECT THE SAME CLRNC; PARTICULARLY WHEN THE WORD 'FOLLOW' IS USED. IN OUR CASE; ACR Y WAS CLRED TO TAXI TO RWY 4; AND WE WERE CLRED TO FOLLOW ACR Y TO TAXI TO RWY 4 AS WELL -- THUS SETTING THE STAGE FOR THIS ERROR. WHEN INSTRUCTIONS DIFFER ONLY SLIGHTLY BTWN 2 ACFT; AND ONE IS FOLLOWING THE OTHER; ATC SHOULD CONSIDER PAUSING; THEN EMPHASIZING THE PORTION OF THE CLRNC WHICH DIFFERS RATHER THAN READING THE ENTIRE CLRNC IN THE SAME RAPID FIRE MANNER. LGA GND CHART STATES; 'CAUTION: ACFT TAXIING ON TXWY B FOR RWY 4 DEP MAY BE INSTRUCTED TO HOLD AT THE ILS HOLD LINE.' THIS BLOCK OF TEXT IS IN SMALL PRINT; AND IS PLACED AS FAR AWAY FROM THE ACTUAL HAZARD AREA AS IT COULD POSSIBLY BE PLACED; YET STILL BE ON THE SAME PAGE. WE SHOULD ENCOURAGE COMMERCIAL CHART COMPANY TO USE A LARGER DASHED LINE FOR THE WARNING BOX GIVEN THE LARGE AMOUNT OF AVAILABLE SPACE THAT'S OTHERWISE WASTED. THE CAUTION TEXT AND BOX AT THE TOP R SHOULD BE INCREASED IN SIZE. THE PHRASE; '...FOR WINGTIP CLRNC FROM LNDG ACFT;' MIGHT BE ADDED TO THE WARNING BOX FOR ADDITIONAL CLARITY AND ENHANCED PLT UNDERSTANDING.