Microscopic Simulation and Safety Analysis of Roundabouts

Faculty Sponsor





Civil Engineering

Presentation Type

Poster Presentation

Symposium Date

Spring 5-2-2015


Although circular junctions are usually associated with the British, their presence in the United States dates back to at least 1905. Those early twentieth century circular junctions, called traffic circles, were designed for high-speed entries into the circular area and gave priority to the entering vehicles over the circulating vehicles. The resulting high crash frequency and choked traffic circles associated with these intersections stopped the spread of circular junctions in the United States. In the 1960s, the United Kingdom introduced the mandatory yield-at-entry rule at circular junctions, which led to the birth of the modern roundabout. Safety is the hallmark of modern roundabouts, as they reduce both the frequency and severity of crashes. The first modern roundabout in the United States was built in Nevada in 1990 and their number is steadily rising since then: 38 in 1997, more than 2,000 in 2010, and over 3,500 at present. Initial resistance by the public usually changes to a favorable response upon the completion of roundabouts. As a result, hundreds of roundabouts are expected to be built each year in the United States. This study presents a microscopic simulation modeling and safety analysis of modern roundabouts. Various microscopic simulation modeling tools were explored for traffic analysis of roundabout operation. For safety analysis, researchers looked at simulation-based surrogate safety analysis model (SSAM) as well as guidelines in the Highway Safety Manual. The proposed roundabout at Laporte-Silhavy and 5-points roundabout in Valparaiso will be studied as field cases and modeled using microscopic traffic simulation.

Biographical Information about Author(s)

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