Impact of pedestrian flows on traffic delays before roundabouts

The paper examines a roundabout located in a residential district of Lviv city. The area has many attraction points, so traffic and pedestrian flow volumes are large. All approaches to the roundabout have unsignalized pedestrian crosswalks, three of which lack safety islands. Field studies were conducted on peak and off-peak periods, collecting primary indicators of traffic and pedestrian flows. Traffic flow delays were determined on the approaches to the roundabout under existing traffic conditions with the help of the PTV VISSIM software. Three options were proposed for arranging pedestrian crosswalks on approaches to the roundabout. The first option was an arrangement of safety islands on all pedestrian crosswalks. The second option was an arrangement of underground pedestrian crosswalks. The third option was the implementation of adapting traffic light control with a call button for pedestrians. Traffic simulation was carried out for all three proposed options with the finding of the delay per vehicle and the values of the average and maximum length of the queue of vehicles on the approaches to the roundabout. All three options showed better results of traffic delay than existing conditions. However, there were delays caused by the traffic flow itself. These delays are seen in the results of the simulation of option two. Traffic delays are the smallest at this option. Option one showed the highest values of traffic delays in comparison with the other two options. The advantages and disadvantages of each option for arranging pedestrian crosswalks are determined. Recommendations are given regarding the feasibility of locating various types of pedestrian crosswalks on the approaches to the roundabout. Given the research results, the best option from the view of traffic and pedestrian flows, their delays and safety is the third one.