What is annual average daily traffic (AADT) and why is it so important for understanding total regional travel?

Annual average daily traffic (AADT) provides a premier look into regional vehicle movement trends. Transportation agencies are enabled to develop smarter planning strategies and construction ideas based on their region’s data.

AADT data is a critical component of an agency’s toolbox, helping them gain a clearer understanding of overall vehicle movement tendencies. From studying this information, they can analyze regional vehicle volumes and create data-driven decisions on how to best improve their transportation networks.

What is annual average daily traffic (AADT)?

AADT is a unit of measurement that is calculated by dividing a road’s yearly vehicle traffic total by 365. This quotient represents the road’s daily vehicle travel mean and is integral to modern transportation planning. By having an accurate daily traffic average to go from for each major thoroughfare in their region, agencies know which transportation areas need improvement the most. This insight allows them to be more strategic with how they allocate resources.

AADT figures can be determined using a transportation planning tool, traffic counting technologies at the road level or manually tallied vehicle counts. Once planners and policymakers have the AADT counts they need, they can test new strategies aimed at improving traffic efficiency.

How is AADT data used?

AADT measurements are used to plan construction projects, enhance infrastructure and formulate new policies. Several important use cases involving AADT data exist, including:

Site selection – Whether it’s being used to choose locations for new electric vehicle (EV) chargers, truck parking or new stores, AADT can assist by showing which roads or highways are the busiest. Roads with higher average traffic totals are typically better for new nearby infrastructure because more drivers will need more stopping options. No matter the type of infrastructure being built, the planners of the project want to make sure it will be heavily used. Deploying a data-driven philosophy when selecting a new construction project location will help verify that it’s in a high-traffic area. This gives stakeholders confidence that the new infrastructure will serve many people and be worth the investment.

Funding determinations – AADT can additionally help agencies identify the level of financial backing needed for a new transportation infrastructure project. Projects set to begin in highly-traveled areas are given more dollars; AADT provides proof of how many vehicles move throughout a region. Based on the level of traffic, accurate amounts of funding can be administered to support a successful project.

Measuring traffic flows and incident impacts – To understand how traffic moves throughout an entire region, AADT totals can be compared on a road-by-road basis. In the event of an infrastructure emergency, AADT data can also help indicate regional impacts the incident is having on surrounding roadways. Study daily vehicle count averages to pinpoint the best ways to manage traffic patterns, no matter the circumstances.

Enhancing equity and safety – Building safer, more equitable transportation infrastructure is another key component that AADT can help with. This data can enable transportation planners to see how traffic numbers by road are changing over time, drawing attention to real-world issues that may be emerging. They’re then able to address these problems that the data helped diagnose, supporting a fairer and safer transportation network for all.

How does AADT paint a vivid picture of total regional travel?

AADT brings a region’s entire transportation profile to the surface by highlighting the traffic disparities between each of its roads and which are the most traveled. Individual AADT counts for each road offer micro-level traffic insights, but when all are analyzed at a bird’s-eye view, it’s easier to spot which parts of a region’s transportation network need the most work.

Comparing year-over-year AADT counts on the same roads additionally shows growth or decline in traffic totals, prompting you to dig deeper into why this could be happening. A holistic, region-wide analysis of AADT data tells the full story of what’s going on in your transportation network, as well as which roads are busiest (or most inefficient). Use this information to allocate resources and funds more responsibly in the pursuit of a more resilient, equitable and safer grid.

The relationship between expansion factors and AADT

AADT data is used to study macro-level transportation trends using expansion factors, which are a way of taking smaller sample sizes of transportation analytics and extrapolating them out to depict an entire region’s travel. Geotab ITS’ expansion factors start with commercial vehicle data recorded by Geotab devices and are compared to Federal Highway Administration (FHWA) ground truths, helping us confidently portray entire regions’ commercial movement.

Beyond expansion factors, Geotab ITS provides AADT insights on a truly granular scale by pulling data into our Altitude platform from FHWA counting stations. Our latest release features a new and improved methodology for calculating AADT estimates, using the best ground truths possible in our calculations. We’ve also expanded into offering AADT counts on primary and secondary roads – rather than exclusively highways – giving planners and estimators even more granular data to work with. Segment-level traffic analytics and better AADT data equips transportation authorities and developers with actionable insights that support smarter planning. In Altitude, regional travel metrics (RTM) is the first module to receive our new AADT methodology (with more to follow).

Developing stronger infrastructure with AADT data as the catalyst

AADT data is the cornerstone of better transportation infrastructure planning, regardless of if it’s being used to inform the site selection of a business project or a public one. Strategically picking new infrastructure locations based on traffic counts results in higher usage and the construction project’s goals being fulfilled. With the power of Geotab ITS’ insights and detailed traffic data analysis, build better transportation networks that account for all of your region’s unique challenges.

Schedule a free demonstration of Altitude today to learn how AADT insights can support a variety of impactful business cases for your organization.