1 / 27

vertical profile 3

For S < L . For S ? L . Assuming h=0.6 m, headlight height; and a ? = 1?, upward divergence of the light beam, For S < L . For S ? L . Sag Vertical CurvesHeadlight Sight Distance. . . The centrifugal acceleration should not exceed 0.3 m/s2. The minimum length of the sag curve is:where: A = change in grade, V = speed in km/h. This requirement is only about 50% of the headlight sight distance. .

lotus
Download Presentation

vertical profile 3

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    1. Vertical Profile (3) Lecture 9 Text: A Policy on Geometric Design, pp.280-283

    6. Sag Vertical Curves

    7. Sight Distance at Undercrossings

    8. Horizontal and Vertical Alignments It is difficult and costly to correct alignment deficiencies after the highway is constructed.

    9. Vertical and horizontal alignments should be balanced (similar number of curves of similar lengths). Vertical curves should be superimposed on horizontal curves or vice versa. No sharp and short horizontal curves should be located near the crests. A horizontal curve longer than a vertical curve is desirable. A horizontal curve should not be introduced near the low point of a pronounced sag curve (causes distorted appearance and crash risk at night).

    10. Combining Alignments Long tangents on two-lane highways secure a sufficient passing sight distance. Horizontal curvature and profile should be as flat as possible at intersections. On divided highways profiles and horizontal alignments should be considered in each direction separately. Depressed facilities in residential areas make less nuisance to the neighborhood. Road alignment should expose attractive scenic views to the motorists.

More Related