The Data Most Carriers Are Sitting On
State DOTs publish annual traffic count data for every paved public road in the United States. Federal Highway Administration HPMS (Highway Performance Monitoring System) data covers over 4 million road segments. Most carriers have access to this data. Fewer use it well.
AADT — Annual Average Daily Traffic — is the headline number. It tells you how many vehicles pass a given point in a day, averaged across the year. High AADT correlates with subscriber density and data consumption demand. But AADT alone misses more than it captures.
The signal for cell tower site selection isn't just how many vehicles pass a point — it's what traffic count data says about who those vehicles represent, where they're going, and what they'll need from your network over the next decade.
What AADT Doesn't Tell You
AADT counts vehicles. It doesn't segment them.
Two highway corridors with identical 75,000 AADT can have radically different subscriber value profiles. One might be a suburban commuter belt: vehicles traveling 8–12 miles to urban employment centers, concentrated in peak morning and evening hours, with high smartphone penetration and significant residential data demand. The other might be a long-haul freight corridor: vehicles traveling 200+ miles between industrial hubs, concentrated throughout the day, with lower subscriber density per vehicle mile but much higher data consumption per active session.
The same raw traffic number. Completely different build case.
Traffic composition data — the percentage of heavy commercial vehicles, light commercial vehicles, and passenger vehicles on a given segment — is the correction. State DOTs collect this via weigh-in-motion stations, automated vehicle classification counters, and field observation. It's available in HPMS as vehicle class distributions.
A corridor with 40% commercial vehicle composition and a 45,000 AADT is a different market than a corridor with 12% commercial composition and 45,000 AADT. The commercial vehicle segment correlates strongly with enterprise subscriber density, B2B revenue, and data plan consumption rates. For mid-market carriers looking at ROI on tower placement, this matters.
Traffic Composition as Subscriber Proxy
When you have traffic composition data, you can segment corridors by subscriber type:
- High commercial, high AADT: Industrial corridors, logistics routes, distribution hub feeders — enterprise subscribers, high data demand, strong roaming revenue potential.
- High commercial, low AADT: Light commercial zones, retail distribution routes — mixed subscriber base, moderate data demand.
- Low commercial, high AADT: Commuter corridors, residential feeders — high consumer subscriber density, residential data demand patterns.
- Low commercial, low AADT: Rural residential routes — low subscriber density, low ROI for any tower type.
The highest-value tower locations cluster in the first two categories. Sites built in the fourth category routinely underperform because carriers were chasing volume, not subscriber composition.
Traffic Trends Over Time
AADT is a snapshot. Trends are the signal.
State DOTs publish multi-year AADT data, typically going back 5–10 years for most segments. A corridor showing 7–10% annual traffic growth is a different opportunity than a corridor holding flat at 75,000 AADT. The growth corridor will cross infrastructure thresholds in 2–4 years that make it viable for new tower deployment. The flat corridor might have crossed that threshold years ago — and may already be served.
For cell tower site selection, traffic trends are a leading indicator:
- The 60,000 AADT threshold: Corridors that hit 60,000–65,000 AADT with growth trajectories become structurally viable for new tower builds — they have enough subscriber demand to justify capital deployment regardless of competitive situation.
- Growth corridors vs. mature corridors: A corridor growing from 35,000 to 55,000 AADT over 5 years has a different ROI profile than a corridor holding at 75,000 AADT for the same period. The first is a first-mover opportunity; the second may already be overserved.
DOT trend data, combined with adjacent population growth vectors, identifies which corridors are approaching viability before competitors run their annual analysis.
Commercial Land Use and Traffic Signal
Traffic count data pairs with land use data to build a more complete subscriber model.
NAICS commercial land use classification — available at the census tract level from the Census Bureau — tells you what commercial activity exists adjacent to a given corridor. Industrial parks, distribution centers, medical facilities, and retail hubs all create subscriber demand.
A coverage gap on a corridor adjacent to a major logistics hub is worth more than the same gap on a corridor adjacent to agricultural land — even if both corridors have identical AADT. The commercial activity around the logistics hub generates enterprise subscriber demand that the agricultural corridor doesn't.
Overlaying commercial land use data against traffic count data lets you score corridors by composite subscriber potential: traffic volume × commercial density × growth trajectory.
The Bottom Line
DOT traffic count data is public, comprehensive, and systematically underused for cell tower site selection.
The correction is simple: layer traffic composition data on top of raw AADT, model corridor-level trends over time, and pair traffic counts with commercial land use data to score subscriber potential. Carriers that do this find tower site opportunities that AADT-only analysis misses — and they find them before competitors run their next build cycle.
For the broader site selection framework that combines traffic with coverage and growth data, see 5 Data Points That Predict Where Carriers Will Build Next. Once you have the site identified, see Small Cell vs. Macro Tower: When the Data Says Go Small to determine the right architecture.
TowerScope integrates DOT traffic count data, vehicle composition analysis, and corridor trend tracking with coverage gap mapping in a single platform. See the data live → Start your 30-day demo