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Related to Both Capacity and Safety for Motorists , Pedestrians and Bicyclists .
| Content Provider | Semantic Scholar |
|---|---|
| Author | Brilon, Werner |
| Abstract | THE HISTORY OF ROUNDABOUTS abouts in France, the United Kingdom and the United States has been well described by Todd. 1,2 Use of roundabouts in Germany in areas such as highway interchanges and urban intersections dates back to the 1930s. However, in the 1960s, for reasons which are unclear, roundabouts fell out of favor and few new installations were designed. By the late 1980s roundabouts were seldom seen in Germany. In the 1980s, German traffic professionals began experimenting with roundabouts to control traffic in both urban and rural settings. Most of these experiments were based on the British model; however, the results of these experiments indicate that the large design roundabouts (rotaries) that are typical in the United Kingdom are not necessarily appropriate for roadways in Germany. Nevertheless, the experiments did indicate that the use of roundabouts can have positive benefits for safety, quality of traffic flow and aesthetics, especially in the more compact installations (see Figure 1). Although many traffic practitioners still associate roundabouts with large installations (often referred to as rotaries), such as that shown in Figure 2, compact roundabouts are now considered to be " state of the art " in Germany and standards for their design and application have been developed. 3,4 As a result of these efforts, roundabouts are now recognized as a useful traffic engineering tool that has applications in urban and rural areas, and many new installations and improvements to conventional intersections have been constructed. Today's standard is the compact, single-lane roundabout, with an outside diameter of approximately 28 to 45 meters (m) [95 to 150 feet (ft.)]. Figure 1 illustrates a typical modern roundabout installation. The remainder of this feature focuses on roundabouts as they are found at modern intersections and on their associated characteristics regarding capacity, safety, aesthetic design and costs. As a clarification, the compact single-lane roundabouts discussed in this feature should not be confused with the traffic circles that are becoming more commonly used as traffic calming devices within neighborhoods. The primary purpose of these neighborhood traffic circles is to create friction along a local street by slowing speeds in hopes to deter cut-through traffic and/or control speeding, which means these traffic circles are not typically designed to the same standards as those referred to here. CAPACITY AND QUALITY OF TRAFFIC FLOW Prior to discussing capacity at modern roundabouts, it is important to note a few key assumptions: a) … |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.ite.org/membersonly/itejournal/pdf/Jka98a48.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
