It was observed that about 70% of vehicles travel in platoons on Indiana highway corridors in the vicinity of urban areas. Many vehicle platoons were halted at signalized intersections to give the right of way to vehicles on the intersecting minor road, even though there were only one or two vehicles on the minor road. This phenomenon suggested that the total traffic delay at an intersection might be reduced if the approaching vehicle platoons on the major road were allowed to pass through the intersection at the expense of a reasonably prolonged delay of the few vehicles on the minor road. Consequently, a study was conducted to investigate vehicle platoon characteristics and to develop control logic for timing actuated traffic signals in terms of the presence of vehicle platoons. This paper presents some findings of the study on traffic flows in terms of vehicle platoons. Included in this paper are the selection of the fundamental platoon variables and determination of the critical headway value for platoon identification, the appropriate platoon detector placement, and the mathematical distributions of the platoon variables.
