NCDOT maintains a significant number of T intersections with developable land occupying the vacant fourth leg. When a need for a fourth leg is established, NCDOT must determine the optimal location of the leg. Common options include adding the leg to the existing intersection as well as moving the leg up or downstream of the existing intersection to create an offset-T configuration.
This report first documented the established literature and knowledge regarding the operational and safety impacts of the offset T-intersection versus the 4-leg intersection. Then, it presented results from a microsimulation-based operational study over five development scenarios, two demand to capacity ratios, and nine intersection geometric designs, which resulted in 90 combinations of simulation scenarios. Queue length and delay were employed as measurements of effectiveness. Based on the simulation effort and associated measures, this research provided practice-ready guidelines to NCDOT on the selection of the optimal intersection geometry for each specific development project. In general, this research recommended the L-R offset T-intersection for new developments given its significant benefits in terms of reducing delay, particularly delay to the major street movements.
