公路线形设计外文文献翻译英文参考.doc

外文文献翻译 () 文献出处：Y Hassan. Geometric Design of Highways[J] Advances in Transportation Studies, 2016, 6(1):31-41. 英文原文 Geometric Design of Highways Y Hassan A. Alignment Design The alignment of a road is shown on the plane view and is a series of straight lines called tangents connected by circular curves. In modern practice it is common to interpose transition or spiral curves between tangents and circular curves. The line shape should be continuous, sudden changes from flat line to small radius curve or sudden change of long line end connected to small radius curve should be avoided, otherwise a traffic accident may occur. Similarly, arcs with different radii end-to-end (complex curves) or short straight lines between two arcs with different radii are bad lines unless an easing curve is inserted between arcs. The long, smooth curve is always a good line because it is beautifully lined and will not be abandoned in the future. However, it is not ideal that the two-way road line shape is composed entirely of curves, because some drivers always hesitate to pass through curved road segments. The long and slow curve is used in the smaller corners. If you use a short curve, you will see kinks. In addition, the design of the flat and vertical sections of the line should be considered comprehensively and should not be only one. No matter which, for example, when the starting point of the flat curve is near the vertex of the vertical curve, serious traffic accidents will occur. Vehicles driving on curved sections are subjected to centrifugal force, and they need a force of the same magnitude in the opposite direction due to the height and lateral friction to offset it. From the viewpoint of highway design, the high or horizontal friction cannot exceed a certain value. The maximum, these control values ??for a certain design speed may limit the curvature of the curve. In general, the curvature of a circular curve is represented by its radius. For the linear design, the curvat