Safety study of a roundabout

Abstract

Roads ensure continuous, safe and convenient movement of vehicles. Intersections play a critical role in the road network in terms of capacity, service level and safety. They are designed in different sizes for different purposes and conditions and have their own defining characteristics that can affect their safety and ease of use.

Particular attention is paid to roundabouts - where traffic slows down and becomes a one-way flow around a central island. Additional entrance and roundabout lanes improve transportation efficiency, but they also have an impact on safety. The safety disadvantage can be due to inappropriate driver behavior when approaching, circling, and exiting the intersection, as well as weaving maneuvers within the roundabout.

The concept of turbo-roundabouts has emerged as a possible alternative to conventional multi-lane intersections, but the analysis of studies does not allow us to draw definitive conclusions about their effectiveness and safety, so it is recommended that such studies be conducted for specific road conditions.

The paper proposes a design of a turbo-roundabouts to improve safety without reducing its efficiency at the intersection of international highways (European route E40 «Kyiv–Chop» and E85 «Domanove-Kovel-Chernivtsi-Terebleche») near the city of Dubno, where traffic accidents regularly occur.

Among the different types of turbo-roundabouts, the basic turbo-roundabouts with a maximum capacity of up to 2,500 vehicles per hour and the largest traffic flow is taken as a basis.

All geometric parameters correspond to the average size of a turbo intersection, take into account the overall dimensions of the truck, the speed of traffic and are built in accordance with the recommendations of regulatory documents of European countries specializing in their design.

The designed turbo intersection with circular traffic has the best comparative option and will reduce the overall accident rate by 36 % and the number of injured people by 34 %.