Before a highway alignment is finalized in highway project, the engineering surveys are to be carried out. The surveys may be completed in four stages such as
– Map study
– Preliminary survey
-Final location and detailed survey
The recent development in the art of preparing topographic maps from aerial photographs has served as an invaluable aid in the selection of route. By careful study of such maps, it is possible to have an idea of several possible alternate routes. So that further details of those may be studied later at site.
Reconnaissance survey is a rapid but though examination of an area or a strip of territory between the termini of the project to determine which of the several possible routes may be worthy of a detailed survey.
At the time reconnaissance we use simple instrument like the reconnaissance party to collect additional data uses level, tangent clinometers and barometer etc…details rapidly (not accurately). All relevant details not available in the map are collected and noted down. Some of the details to be collected during reconnaissance are given below.
1. Distances are usually taken from the reference maps
2. The directions of line may be observed by means of a prismatic compass.
3. The relative elevation of point determined directly from the topographic map.
4. The relative slope of the ground or appropriate different in elevation obtained by use of a level or clinometers
The notes and records may be marked on an existing map, or notes may be kept separately in a narrative form. The reconnaissance map sketched on an existing map on made separately should show the several routes that are practicable, the control point important topographic features and all others details that may possible be helpful in selection of the route.
The main objectives of preliminary survey are
• To survey the various alternative alignment proposed after the reconnaissance and to collect all the necessary information and details of topography, drainage and soil.
• To camper the different proposal in view of requirements of the road alignment.
• To estimate quantity of earthwork martial another construction aspects for to workout the cost alternative proposal.
• To finalize the best alignment from all considerations.
Final location and Detail survey
E state he alignment finalized at the designing office after the preliminary survey is first located of the field by establishing the centerline. Next detail survey should be carried out after collection the information necessary for preparation of plans and construction details form highway project
The center line road finalized in the drawings is to be finalized on the ground during location survey. In detail survey we consider different information of the route (road)
like earth work calculation and drainage details are to be worked out from level notes, topographical detail are noted dawn and also plotted using covenantal sign ,hydrological details are also collected and detailed silo survey carried out, etc. The data collected during detailed survey should be celebrated and complete for preparing detailed plans and of the project.
Highway developments and planning
Importance of Highway planning
Pliliminary the basic requirement for new project and as well as for examination
Planning survey consists of the following studies
1. Economic studies
2. Financial studies
3. Traffic or road use studies
4. Engineering studies
The principle in transportation planning process may be identified as:-
1. Formulation of objectives
2. Establishment of quantifiable relationship between the present day movement, and use, population and economic features.
3. Collection of land uses population, economic and travel pattern.
4. Prediction of land use, population, economic factor at a design life of the road.
5. Prediction of origin, destination and distribution of future movement.