Two-Level Signalized Intersection

Abstract

Severe traffic congestion often occurs at intersections of high-volume traffic arteries. To reduce this congestion, innovative intersection designs such as the single-point urban interchange (SPUI), center-turn overpass (CTO), and echelon interchange (EI) have been implemented. This paper introduces a new type of intersection, the two-level signalized intersection (TLSI), which improves the efficiency of intersection operations under a wide variety of traffic conditions. The paper compares the TLSI with other innovative intersection types. Unlike the SPUI, CTO, or EI, the TLSI provides for complete separation of east–west and north–south traffic. The TLSI also enables the use of directional separation and leading, lagging, or overlapping lefts on both upper and lower levels. Simulation results indicate that, compared with these other innovative intersection types, the TLSI has the shortest delay times in most evaluation scenarios as well as the least sensitivity to variations in traffic volume. However, the TLSI shows significant delay when traffic volumes on the major and minor roads are vastly different.