Nevada Roundabout Implementation Guidelines

PDFTech ReportReport No. 079-10-803Traffic circlesRoundaboutsTraffic accidentsTraffic safetyLocationPlanning and designUnited StatesNevadaNevada. Dept. of TransportationAhiamadi, Samuel KofiTian, ZongGibby, Adrain ReedUniversity of Nevada, Reno. Center for Advanced Transportation Education and ResearchUniversity of Nevada, Reno. Department of Civil and Environmental EngineeringNevada. Dept. of TransportationUniversity Transportation Centers Program (U.S.)US Transportation CollectionIn 1990 Nevada constructed the first modern roundabout in the U.S. and since then several roundabouts have been constructed with most operating successfully; the U.S. currently has over forty-five states with at least one modern roundabouts. Due to their safety performance and operational efficiency roundabouts have gained popularity among transportation practitioners and the general public. As an intersection control, roundabouts operate efficiently with minimal cost under a wide variety of conditions. Based on United States and international experience, roundabouts are known to reduce delay, total crashes and crash severity for intersections with low to medium traffic volume. After the introduction of roundabouts into the U.S., several national research efforts were initiated and the findings provided important information for analysis and design. The most prominent research publications include: 1) National Cooperative Highway Research Program (NCHRP) Report 672 - Roundabouts: An Information Guide, Second Edition, co-funded by Transportation Research Board (TRB) and Federal Highway Administration (FHWA), 2) NCHRP Report 572 - Roundabouts in the United States funded by the TRB 3) Highway Capacity Manual (HCM) 2010 (chapters 21 and 33) funded by the TRB. After the national initiative, several states developed their state specific guidelines which adopted most of the national findings but sometimes deviated depending on the states\u2019 experience and research. Nevada, despite having about 81 roundabouts, lacks a statewide guideline for selection/installation. In anticipation of more roundabouts being constructed in the state, the Nevada Department of Transportation (NDOT) funded this research project, Development of Guidelines for Implementing Roundabouts in Nevada