翻译短文!

Bridge and Alignment
Formerly ,the bridge indicates the alignment of the rode .if possible, the bridge was built at right angles to the river or railroad, even when the road had then to the linked up with curves. In elevation too, steep ramps were chosen with a small radius of summit. Nowadays, the alignment of the rode governs the design of the bridge and the bridge engineer is well advised to accept this subordination, provided that the alignment is good. This change of attitude has arisen as result of the requirements of high speed driving and by the challenge to achieve a steady, good looking road in the landscape.
To design a good alignment for a road nowadays has become a great art requiring the consideration of many factors. One has learned, for example, that long straight sections may lull drivers to sleep and are therefore dangerous. One has learned that curves in plan must be seen in space in combination with curves and slopes in elevation. Easement curve was introduced, whereby curvature changes steadily form a straight line to the desired radius. The integration of a planned alignment into the environment is usually checked by perspective computer drawings as seen from different sight points.
Bridges are a part of the alignment and it is evident these days that the bridge must be adapted to it .This means that bridges often lie within plan curvature and that they follow the slopes or curvature in elevation. The radii of curvature are generally large in order to achieve adequate range of vision. Such large radii are also desirable for aesthetic reasons.