In 2002, a team led by Kittelson & Associates, Inc., was selected to lead a study of roundabouts in the United States. One of the primary objectives of this study, funded through the National Cooperative Highway Research Program and noted as NCHRP 3-65, is to develop a new set of predictive models to estimate the safety and operational impacts of roundabouts. In order to model driver behavior and performance, it is necessary to have information on how drivers behave when using traffic facilities of various designs and characteristics. Thus one of the important elements of this study was to assemble a database of facility operation and safety for a wide variety of roundabout sites in the United States. In this paper, the authors describe their process for collecting, extracting, and summarizing data at roundabouts. The data were collected during the spring and summer 2003, and were extracted and summarized during the fall 2003 and winter 2004. This database is now the largest that has ever been assembled for roundabouts in the United States. Section 2 of this paper provides an overview of the characteristics of the more than 300 modern roundabouts that exist today in the United States. Section 3 describes the process that was used to collect and record data in the field. Section 4 describes how the data were extracted from the field records. Section 5 describes the database that has now been assembled.
Samenvatting