Highway surveys are a professional type of land survey during the planning phases of a road project. As-built surveys during the construction process will ensure that progress is made according to the design, and the highway is built exactly where it needs to be. After the completion of the highway, further surveying is typically required for the layout of specific roadways, infrastructure, stormwater drainage systems, and other landscape features.
A land surveyor will typically participate in the road placement process. Initial topographic surveying and production of detailed maps will allow for the analysis of the current ground to find the best path for the roadway. In particular, road building surveys deal with areas where the dirt needs to get pushed and put into the exact level for it. The purpose of the survey is to decide the right route for moving the least amount of land possible.
Surveyors will also help engineers map out optimal routes. This can involve grading (slopes), curves, and tunnel building and possibly other features along the route. Before you try to decide the best route to position the highway, there is a need to understand the existing geographical features of an area by getting it surveyed.
Due to the natural scenery, existing buildings and other things, highways typically wind their way through the landscape rather than in entire lengths of straight highway. The biggest challenge of road planning is that bridges or tunnels are required. Surveyors can provide information on their positions and track the road building process to make sure they are placed in the correct position and location.
During highway construction, surveyors will be needed to help mark out limits of the construction area, slope staking to align the surface, and setting reference control points to used throughout the project. Adequate checking and inspecting of built surfaces are done to ensure compliance with design.
Surveying of completed roadways can be done using a combination of conventional total stations, and GPS receivers. More recently, laser scanning systems produce extremely precise data, allowing detailed 3D maps to be made, which can indicate the road and the barriers, overhead wires, and other features.