Comparison of Traffic Flow Characteristics of Signal Controlled Intersection and Turbo Roundabout

Abstract

In the Slovak republic, there is an increase of building roundabouts in both urban and non-build-up areas. The construction of roundabouts in urban areas brings mainly calming of traffic intensity. A roundabout in non-build-up areas could be built only within certain conditions. In this paper, we have been studying a small roundabout location and its traffic characteristics in the city of Hlohovec. In some cases, a small roundabout could be very good solution for exceeded traffic flow capacity of signal controlled intersections as well as for intersections with a high number of traffic incidents. But in our case, a small roundabout is not suitable for such intensity of vehicles as we measured in transport survey. So we focused on other possibilities how to improve this current situation. We have decided to make a proposal of signal controlled intersection as well as a turbo roundabout and compare the results of traffic characteristics of each proposal. We have made several simulations of each variant of traffic situation, using transport-planning software Aimsun, and calculate average values of all recorded traffic characteristics. As inputs, we have used intensities and other basic data obtained from transport survey. Using simulations outputs of transport planning software, we have been able to compare a current state with signal controlled intersection and turbo roundabout. Traffic characteristics of turbo roundabout show significant improvements compare to signal controlled intersection, f.e. in delay time (more than 68 %), travel time (more than 22 %), number of stops (more than 73 %). Turbo roundabout seems to be the best solution for traffic organising at this chosen intersection in the city of Hlohovec, regarding travel time, delays, number of stops and safety at all.