Narrative:

Taking a look at iah 70-9 airport chart, clearly idents all the double-letter idents for every taxiway. I understand the 'north' for north, 'south' for south, 'west' for west, and 'east' for east prefix system. However, iah doesn't even have enough txwys to exhaust the basic 26 letters of the alphabet. I have sat on the ground at iah and listened to all the congestion and many times confusion on the ground frequency due entirely to this double-letter system. I am sure that a few day's analysis of the ground control frequency will show an inordinate amount of radio chatter as compared to other airports with the same traffic volume. Specifically, analyze the number of corrections to readbacks and the amount of time controllers spend on repeating taxi instructions to eliminate pilot confusion. This double-letter identify is a perfect example of taking a very efficient and simple system of controling aircraft on the ground and making it confusing, complicated, dangerous and unnecessary! Callback conversation with iah area supervisor revealed the following information: the taxiway identify system at iah is set up to distinguish the 3 runways, and the associated area of the airport they occupy, from one another, ie, north, south, and west. In addition, the number of txwys out numbers the letters of the alphabet, so some sort of number or double letter combination was necessary. The latter was used.

Google
 

Original NASA ASRS Text

Title: A CARJ CAPT EXPRESSES HOW HE THINKS THE DOUBLE-LETTER TXWY IDENT SYS AT IAH PRESENTS UNNECESSARY AND DANGEROUS CONFUSION.

Narrative: TAKING A LOOK AT IAH 70-9 ARPT CHART, CLRLY IDENTS ALL THE DOUBLE-LETTER IDENTS FOR EVERY TXWY. I UNDERSTAND THE 'N' FOR NORTH, 'S' FOR SOUTH, 'W' FOR WEST, AND 'E' FOR EAST PREFIX SYS. HOWEVER, IAH DOESN'T EVEN HAVE ENOUGH TXWYS TO EXHAUST THE BASIC 26 LETTERS OF THE ALPHABET. I HAVE SAT ON THE GND AT IAH AND LISTENED TO ALL THE CONGESTION AND MANY TIMES CONFUSION ON THE GND FREQ DUE ENTIRELY TO THIS DOUBLE-LETTER SYS. I AM SURE THAT A FEW DAY'S ANALYSIS OF THE GND CTL FREQ WILL SHOW AN INORDINATE AMOUNT OF RADIO CHATTER AS COMPARED TO OTHER ARPTS WITH THE SAME TFC VOLUME. SPECIFICALLY, ANALYZE THE NUMBER OF CORRECTIONS TO READBACKS AND THE AMOUNT OF TIME CTLRS SPEND ON REPEATING TAXI INSTRUCTIONS TO ELIMINATE PLT CONFUSION. THIS DOUBLE-LETTER IDENT IS A PERFECT EXAMPLE OF TAKING A VERY EFFICIENT AND SIMPLE SYS OF CTLING ACFT ON THE GND AND MAKING IT CONFUSING, COMPLICATED, DANGEROUS AND UNNECESSARY! CALLBACK CONVERSATION WITH IAH AREA SUPVR REVEALED THE FOLLOWING INFO: THE TXWY IDENT SYS AT IAH IS SET UP TO DISTINGUISH THE 3 RWYS, AND THE ASSOCIATED AREA OF THE ARPT THEY OCCUPY, FROM ONE ANOTHER, IE, N, S, AND W. IN ADDITION, THE NUMBER OF TXWYS OUT NUMBERS THE LETTERS OF THE ALPHABET, SO SOME SORT OF NUMBER OR DOUBLE LETTER COMBINATION WAS NECESSARY. THE LATTER WAS USED.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.