A MEM TWR CTLR RPTS A C421 ATTEMPTED TKOF FROM TXWY S.

Narrative

I WAS WORKING LOCAL 2 AND 3 (LC1/LC2) COMBINED DURING AFTERNOON AIRLINE INBOUND/OUTBOUND PUSH. A C421 HAD TAXIED FROM COMPANY X VIA TXWY B; AND HAD BEEN INSTRUCTED BY GND 2 (GS2) TO; 'HOLD SHORT OF TXWY S; CONTACT TWR 119.7.' THE PLT CALLED ME AND STATED THAT HE WAS READY TO DEP. AT THE TIME; MEM WAS LNDG RWYS 18L AND 18R; AND DEPARTING RWY 18C. MANY ACFT LNDG RWY 18L ARE INSTRUCTED TO; 'TURN RIGHT; JOIN TXWY S NBOUND.' I ISSUED THE WIND AND CLRED THE C421 FOR TKOF. AFTER SCANNING DOWN THE RWY; MY EYES CAME BACK TO THE CESSNA AND THE ACFT HAD STARTED ROLLING DOWN TXWY S! I IMMEDIATELY CANCELLED THE TKOF CLRNC AND TOLD THE PLT TO STOP. ONCE THE ACFT CAME TO A HALT; I DIRECTED THE PLT TO RWY 18C. THANKFULLY THERE WERE NO LNDG ACFT EXITING RWY 18L ONTO TXWY S. AFTER THIS EVENT; NEARLY EVERY CTLR IN THE TWR TOLD OF A SIMILAR STORY INVOLVING TXWY S. APPARENTLY THE INTXN OF TXWYS B AND S ARE VERY CONFUSING. WE SHOULD LOOK INTO CHANGING THE MARKINGS OR CHANGING OUR TECHNIQUE IN THE TWR FOR MORE SPECIFIC HOLD SHORT OR DEP INFO.