This report describes a study of the delineation requirements for work zone traffic control. The research included a comprehensive review of past studies and current practices, and an examination of current standards. It was concluded that, in spite of the increasing number of different types of channelizing devices, there appears to be no scientific basis for the spacing criteria for the use of devices for channelization purposes in the taper or tangent sections of a work zone. A laboratory-based testing procedure was used to determine the most appropriate spacing configuration. An interactive video system was used to test subject recognition distances of eight different device types spaced at the standard distance, 1.5 times and 2.0 times the standard distance. Over 240 subjects were tested.