Shirley, Just a thought. Why not create a dummy X detector in controller conditioning such that (X left or X right)=Dummy X. You could use this Dummy X as the X sink for the ahead movement. I appreciate that there will be times when this combined loop undercounts, due to both loops being occupied simultaneously, but the only effect this will have is the possibility of giving slightly longer green times to the ahead movement. Terry Gardner Traffic Systems Engineer Glamorgan Engineering Consultancy Tel: 02920820683 ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the sender and delete from your system. Any views or opinions expressed in this email are those of the individual and not necessarily that of Glamorgan Engineering Consultancy. ********************************************************************** ----------------------------------------------------------- A message from the TCUG mailing list. For information about the list visit //www.freelists.org/webpage/tcug