Annual average daily traffic (AADT) & Average daily traffic (ADT)

Annual average daily traffic (AADT)

Annual average daily traffic, abbreviated AADT, is a measure used primarily in transportation planning and transportation engineering. Traditionally, vehicle traffic is the total volume on a highway or road for a year divided by 365 days. AADT is a useful and simple measurement of how busy the road is. Newer advances from traffic data providers are now providing AADT by side of the road, by day of the week, and by the time of day.

AADT Computed:

The annual average daily traffic (AADT) = ADT X DF X WF X SF

Here,

ADT = Average daily traffic.

DF = Daily factor.

WF = Weekly factor.

SF = Seasonal factor.

Average daily traffic (ADT)

Average daily traffic or ADT, and sometimes also mean daily traffic, is the average number of vehicles two-way passing a specific point in a 24- hour period, normally measured throughout a year. ADT is not as highly referred to as the engineering standard of AADT which is the standard measurement for vehicle traffic load on a section of road, and the basis for most decisions regarding transport planning, or to the environmental hazards of pollution-related to road transport.

ADT = Traffic volume count x DF x SF.

Hear,

DF = Daily factor.

SF = Seasonal factor.

Design hourly volume and capacity

The general unit for measuring traffic on the highway is the Annual Average Daily Traffic volume, abbreviated as AADT. The traffic flow volume fluctuates with time, from a low value during off-peak hours to the highest value during peak hours. It will be uneconomical to design the roadway facilities for the design and this is called Design Hourly Volume (DHV) which is determined from extensive traffic volume studies. The ratio of volume to capacity affects the level of service of the road. The geometric design is thus based on this design volume, capacity, etc.