Road Construction Procedures

Mapping

• Before construction ever begins, extensive mapping takes place. Surveyors map the entire area to pinpoint where the new road will sit. Once complete, adjacent homes are mapped and if necessary, bought out through the government's right of eminent domain, which occurs if the property falls within the new road's right-of-way. Surveyors note the topography of the surrounding area, such as mountains, streams and lakes, and place the new road accordingly. Benchmarks are mapped every 1000 feet for the entire length, referencing elevation in comparison to sea level and signifying the future preferred elevation of the road.

Ground Assessment

• Once surveyors have completed mapping the area, they must next assess the ground for road suitability. Workers take soil samples using a drill rig or hand auger, with a minimum of 25 samples every mile. These samples stretch out to 100 feet on either side of the new highway and once analyzed, lead to a classification of the area's soil profile. Swamps, lakes, rivers and other wetlands require more surveys and assessments, not only to determine the ecological impact of a new roadway but also to determine suitability.

Earthwork

• Once the government has completed all the mapping, property acquisition and soil studies, actual groundwork can begin. Workers place survey posts every 100 feet on the new road's centerline and at the right of way limits and removal of trees and brush begins. After workers have cleared the brush, they place construction stakes on the centerline, slope stakes, stakes for culverts, storm drains and curbs.

Landscaping and Paving

• Workers place blue stakes every 100 feet and begin to landscape the ground to meet the pre-mapped elevation benchmarks. With the "blue tops" on the surface, contractors perform a final touch to the dirt road. Then workers begin to lay an aggregate, or a rocky, densely-packed substance, to the landscaped dirt as a base, followed later by asphalt and other surface materials.

Finishing Touches

• Workers apply paint to the finished road and begin work on slopes and ditch bottoms to try and prevent erosion. They place stakes for various erosion control materials, such as straw and rock. Workers apply paint to the new road. Final measurements will determine the quality of the road construction job, as well as whether the road meets legally-required standards. These factors play into the contractor's final pay.

Maintenance

• Over time, the new road will experience damage due to weather and use. Chips will develop in the pavement from freezing water, encroaching plants, snow chains and more. Sometimes existing roadways need expansion to handle an increasing amount of traffic. Roads undergo repaving, repainting and more to stay in operation.