==>>RECONNAISSANCE SURVEY FOR HIGHWAY LOCATION IN RURAL AREA<<==

==>>RECONNAISSANCE SURVEY FOR HIGHWAY LOCATION IN RURAL AREA<<==

Two methods;==>>

1. ==>>Conventional ground method.
2. ==>>Aerial photography.

1. CONVENTIONAL GROUND METHOD:==>>

In this method a field survey party inspects a fairly broad stretch of land along the proposed alternative routes of the map in the field.
Intensive reconnaissance is very important for highway location in a new country as well as where completes abandonment and replacement of an existing road are planned.

1. Initially help is taken from already available maps, particularly topographic maps of the area so that most promising general route may be laid out for careful inspection on the ground.
2. Once a route selected on the map by crude but rapid survey method, a survey is made along the path   selected on the map.
3. PRIMARY CONTROLS==>> are then established after it which include
   
   1. Terminal of the road and intermediate points through which it must pass.
   2. Single mountain pass if no alternative exists.
   3. Small settlements, for secondary roads.
4. SECONDARY CONTROLS: ==>>Once primary controls are established the secondary controls are then considered which include;
   1. Drainage system.
   2. Mountain passes.
   3. Low points in ridges.
   4. Cost factors such as favorable and unfavorable soil conditions, the number and sizes of structures, the amount of excavation and embankment, alignment and grade.
5. POSSIBLE ALIGNMENT==>>
   1. In mountainous country with well defined summit ranges, there is usually a suitable pass along the drainage on both sides.
   2. The least expensive and frequently the straightest line may lie just above high water in streams often; however, the rise of valley may exceed the maximum permissible grade.
   3. At times a more favorable location lies on the hillside at some height above the stream.
6. MOUNTAIN LOCATION: ==>> On occasion, the route must climb from stream level to an adjoining pass or summit. The road must be long enough to provide for the required gain in elevation at max permissible rate.
7. Depending sooner from the level valley will result in climbing to summit in less grade and moderate curvature.
   Excessive use of switch backs should be avoided.
8. IN SNOW LOCATION: ==>> In sow areas locations should be confined to slopes exposed to the  sun in order to avoid icing on the roadway and ease snow removal problems..

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