How is Average Daily Traffic (ADT) defined?

Average Daily Traffic (ADT) is defined as the total volume of traffic on a roadway segment over a specified period, typically one year, divided by the number of days in that period. This measure provides an average number of vehicles passing a specific point on a road per day, allowing traffic engineers and planners to assess roadway usage and make informed decisions regarding infrastructure needs, traffic flow improvements, and safety measures.

Option C captures this definition accurately, as it describes the process of summing the total traffic volume and then normalizing this figure to a daily average over a certain timeframe. This conceptualization is essential for traffic analysis because ADT serves as a fundamental metric in traffic engineering, influencing roadway design, capacity planning, and resource allocation.

Other options do not align with this definition of ADT. For instance, one option refers to traffic volumes during peak hours, which do not represent the average traffic over an entire day. Another option focuses on a weekly average rather than a daily metric, which deviates from ADT's specific definition. The final choice looks at traffic counts within an hour, which, while useful for understanding peak conditions, does not capture the average traffic flow over a full day.