Traffic Operations Analysis of Seven New Alternative Intersections with Three-Phase Traffic Signals

Abstract

This paper presents a traffic operational comparison of seven new alternative signalized intersection designs with three critical phases: 1) offset thru-cut, 2) thru-cut, 3) seven-phase, 4) redirect left and through from one minor road (redirect L&T), 5) reverse reduced conflict intersection (reverse RCI), and 6) and 7) two new versions of partial median U-turn (MUT) intersection. These designs will also be compared with the four-phase conventional intersection and two alternatives with two-phase traffic signals: full MUT and reduced conflict intersection (RCI) designs under various traffic conditions at near-capacity levels. Overall, 1,800 simulation runs were conducted to estimate traffic operations under different traffic conditions with varying traffic volumes, traffic distributions, and turning traffic ratios. Traffic signals were optimized for all the tests, and the optimized signal data was imported into microsimulation to evaluate the performance of the 10 intersections included. According to the results, four of the three-phase intersection designs (offset thru-cut, thru-cut, MUT #1, and reverse RCI) could result in significantly shorter travel times than the conventional intersection. The traffic operations of these four intersection designs were found to be similar to the two-phase designs and even better than the full MUT in scenarios with high turning traffic ratios. The other three intersection designs (seven-phase, redirect L&T, and MUT #2) also showed potential as possible substitutes for existing four-phase intersections under conditions with higher turning traffic demands.