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Average Daily Traffic
According to NCHRP Report 765, average daily traffic (ADT) reflects the average number of vehicles that travel through a segment of roadway over a short-term period. The ADT is the raw, non-factored count data obtained by a short-term traffic count (usually a 24- to 48-hour period) typically collected on Tuesday, Wednesday, and Thursday. The ADT is an important, basic unit of traffic monitoring and is essential for developing traffic forecasts.