lecture 7 part II// lecture 7 part I is solved examples// tues, feb 27,2018 you was there but you did not have the copybook. Flashcards
Highway location process includes 4 main phases
Office study of existing information
Reconnaissance survey( field investigation to verify conditions from the desk study and collect additional info)
Preliminary location survey
Final location survey
Terrain categories
level/flat terrain
sight distances are generally long or can be
made to be so without construction difficulty
rolling terrain
occasional steep slopes which restrict alignment
Mountainous terrain
frequent changes in ground elevations, heavy work needed
Sources of information for determining route location
topograhic maps Aerial photography geological and soil maps ground surveys (surveying equipment)
Highway geometric design pocess
step one specify design standards step two identify site characteristics step three identify design controls step four select routes for preliminary design step five conduct preliminary design step six evaluate alternatives step seven conduct detailed design of selected alternative
Functional classification of urban roads
1-Arterial roads
serve major traffic
2-Local roads
collect traffic from local streets and channel it to arterial roads
3-local roads
access to land is the primary purpose (not intended for traffic)
Functional classification of rural roads
1-Arterials
Serve trips between urban areas
2-Connectors
connect cities and large towns in rural areas
3-local roads
Serve traffic within rural areas and connect villages not served by arterial system.
Mobility vs. access
Mobility: moving within traffic
access:access to land, properties…
There is a graph page 43 look at it (higher mobility lower access and vice versa)
Routes must be technically feasible meaning
there is a compromise between user cost and construction cost
look at graph page 50.
