What factors contribute to the cost estimation in highway projects?

The correct response identifies a comprehensive set of factors that are critical for cost estimation in highway projects. Labor costs encompass wages and benefits for the workers involved, while materials include all physical components needed for construction, such as asphalt, concrete, and steel. Equipment costs cover the machinery used for different phases of the project, including rental or purchase expenses. Overhead costs represent administrative expenses that are not directly tied to a specific project task but are necessary to keep the project running smoothly. Finally, project duration is essential, as longer projects may incur additional costs due to inflation, extended wages, and equipment maintenance.

Considering this, the other options do not capture the full range of expenses involved in highway projects. While geographical location and available technology can impact costs, they are not all-encompassing enough to address the complexities involved in cost estimation as thoroughly as the selected response. Similarly, weather conditions and public opinion may influence project timelines and perceptions but do not directly correlate with the detailed financial breakdown necessary for comprehensive cost estimation. The outlined factors in the correct answer provide a well-rounded understanding of what influences costs in highway construction projects.