1. Highway Location I. * Principles of Highway Location 1. allowing convenient, continuous, free-flowing traffic operation, and 2. best meeting the major traffic desire lines and being as direct as possible. II. *Highway Location Practice 1. Keep grades and curvature to the minimum 2. Avoid sudden changes in sight distance, especially near junctions sight distancesight distance 3. Avoid having the beginning or end of a sharp horizontal curve on or adjacent to a pronounced vertical curve 4. Site the highway through undeveloped areas in urban areas, along the edges of large parklands and away from expensive land areas 1 Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015

2. Highway Location II. Highway Location Practice 5. Seek locations which result in the least amount of environmental unfavorable impact (visual and audio) to affected householders 6. In urban areas locate the highway as close as possible to the principle parking terminals 7. In rural areas locate as much as possible of the new highway on existing ones, so as to minimize the loss of farmland and to reduce the total initial and maintenance costs 8. Locate the highway along the edges of properties rather than through the middle 9. Avoid the destruction or removal of man-made culture 2 Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015

3. Highway Location II. Highway Location Practice 10. Keep the highway away from cemeteries, places of worship, hospitals, schools and playground 11. Consider the effect of the proposed highway on existing or future utilities above, on or under the ground 12. Never have two roads intersecting near a bent or at the top or bottom of a hill 13. In the case of a motorway, economically locate an interchange at a place, at an angle and in terrain 14. Avoid intersections at-grade with railway lines, the highway passing over the railway at a point where the railway goes into a cutting 15. Seek favorable sites for river crossings at right-angles to the stream centerline 3 Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015

4. Highway Location II. Highway Location Practice 16. Do not have a bridge or tunnel located on or adjacent to a highway curve 17. Avoid the need for deep cuttings and expensive tunnel construction 18. Avoid locations where rock is close to the surface 19. In hilly terrain reduce the maximum gradient to the lowest value possible 20. To minimize drainage problems, select a location on high ground in preference to one in a valley 21. Avoid bogs, marshes and other low-lying lands subject to flooding 22. Locate the highway on soil which will require the least pavement thickness above it 4 Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015

5. Highway Location II. Highway Location Practice 23. Locate the highway adjacent to sources of construction materials, if possible 24. If possible, the best location is the one which results in the minimum total cost of earthworks, i. e., the minimum quantities of excavation equals that of embankment as to require a minimum of haulage with little need for overhaul 25. In hilly terrain the highway should cross ridges at their lowest points for cheaper construction and more economical vehicle operating costs 26. Avoid creating severe breaks in the natural skyline 27. In hilly country, select a location subject to sunlight so that moisture or snow and ice on the carriageway can evaporate, melt and dissipate 5 Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015

6. Highway Location II. Highway Location Practice 28. Avoid the unnecessary and expensive destruction of wooded areas. If intrusion is unavoidable, the road should be on a curve, where possible, so as to preserve an unbroken background. 29. Avoid ground subject to subsidence or landslip. 30. Avoid placing the highway at right-angles to a series of natural drainage channels. III. Homework What would be the common practices in highway location? What would be the common practices in highway location? What should be paid attention to at intersections for a highway location? What should be paid attention to at intersections for a highway location? 6 Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015

7. Highway Location Sight distance is the length of highway visible ahead to the driver of a vehicle. The three types of sight distance common in roadway design are intersection sight distance, stopping sight distance, and passing sight distance. Back 7 Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015Wednesday, October 21, 2015