Every site selection decision involves cross-referencing data from multiple sources. A site that looks attractive on a traffic map may be three miles from an existing tower that already serves the corridor. A high-AADT station may sit in a census block that is declining in population — not growing.
This is the minimum viable data stack for any site selection decision: five sources, each providing a distinct signal, that together give you a high-confidence site recommendation.
Source 1: State DOT Traffic Counts
What it is: Annual Average Daily Traffic (AADT) counts by vehicle class, measured at fixed counting stations along US highways. Published by state Departments of Transportation, with station locations geocoded.
Why it matters: AADT is the primary proxy for wireless demand density. A station at 35,000 AADT has roughly 3x the user demand of a station at 12,000 AADT. Beyond volume, the vehicle classification breakdown tells you whether the corridor serves commuter traffic, freight, or recreation — each with different capacity demands and co-location appeal.
What to extract: Station-level AADT (not route averages), year-over-year trend for the last 3–5 years, vehicle class breakdown (FHWA Scheme F or Scheme V), and direction-of-travel splits if available.
Where to get it: Most state DOTs publish data via their open data portals or the FHWA HPMS (Highway Performance Monitoring System). Station-level counts are often available as downloadable CSV or via API.
For a full walkthrough of reading a DOT traffic count report, see our guide on How to Read a Traffic Count Report for Cell Tower Placement.
Source 2: FCC Coverage Data
What it is: FCC Form 477 data — carrier-reported coverage maps by census block, filed biannually by all licensed wireless providers. Shows where each carrier claims to have service and at what technology level (5G, LTE, 3G, or no service).
Why it matters: FCC 477 data reveals whether a high-traffic station is covered or uncovered. A station at 40,000 AADT with two strong-signal LTE carriers is not an opportunity — it is a competitive saturation problem. The same 40,000-AADT station with no usable signal and a 5-mile gap in carrier coverage is the starting point for a build recommendation.
What to extract: Carrier presence (which carriers report service at the station), technology generation (4G/LTE vs. 5G), and signal quality proxy (census block-level data approximates signal strength via technology and spectrum band).
Limitations: FCC 477 data is self-reported by carriers and tends to overstate coverage (carriers claim credit for areas they serve at the block level even if coverage is marginal). Treat it as a screening tool, not a ground-truth signal map.
Source 3: US Census Bureau Population Data
What it is: Annual population estimates and decennial census counts at the county, census tract, and block group level. ACS (American Community Survey) 5-year estimates provide income, age, and housing data for smaller geographies.
Why it matters: Highway traffic is not static — it shifts as population centers grow or decline. A corridor passing through a county growing at 2.5% annually has a structural growth tailwind that will sustain or increase demand over a 20-year tower lifecycle. A corridor passing through a county losing population at 0.5% annually is fighting a demographic headwind.
Population growth also correlates with commercial development, which drives additional small cell and DAS demand on adjacent infrastructure. A tower near an expanding commercial node has more upgrade and expansion potential than one in a stable residential zone.
What to extract: County or census tract population growth rate over the last 5–10 years, projected growth (state-level projections available from most state demographers), income growth, and housing unit growth.
Source 4: Local Building Permit Activity
What it is: Building permit records published by municipal and county planning departments. In most jurisdictions, permits are public record and available through the planning department or online portal.
Why it matters: Building permit activity is a leading indicator of commercial and residential development. A corridor with rising building permits signals that the surrounding area is attracting investment — more rooftops, more commercial tenants, more wireless demand. A corridor with flat or declining permit activity has a stable but non-expanding demand base.
For tower siting specifically, building permits also reveal competitor activity: if a developer recently filed permits for a new cell tower within 5 miles of your target site, the competitive environment is changing.
What to extract: New commercial construction permits (office, retail, industrial), new residential permits, utility permits for fiber or power extension (these indicate backhaul planning activity in the corridor).
Where to get it: Many municipalities publish permit data via open data portals (Socrata, OpenDataSoft). For smaller jurisdictions, a direct request to the planning department is often the fastest path.
Source 5: Existing Tower Database (FCC ASR)
What it is: The FCC Antenna Structure Registration (ASR) database — every registered tower structure in the US with location, height, and ownership information.
Why it matters: ASR data tells you the existing tower inventory within a radius of your target site. If there are four macro towers within 3 miles, the market is already served and your site faces structural competition regardless of traffic demand. If the nearest registered tower is 8 miles away, you are in a gap that ASR data confirms is genuinely unserved.
What to extract: Registered tower locations and distances from target site, tower heights, ownership (if publicly listed), and technology type where available from public filings.
Limitations: ASR does not capture small cell nodes, DAS nodes, or informal structures. Cross-reference against field data when evaluating dense urban corridors.
Cross-Referencing: How the Data Works Together
No single source gives you a complete picture. The signal comes from combining them:
- High AADT + uncovered by carriers + growing population + active building permits = high-confidence build recommendation
- High AADT + strong multi-carrier coverage + declining population = avoid, even if traffic is high
- Medium AADT + uncovered + flat population growth + distant existing towers = evaluate economics carefully before committing
The cross-reference workflow is time-intensive if done manually. TowerScope pulls all five sources into a single interface — traffic counts, FCC coverage grades, census growth rates, building permit activity signals, and ASR tower proximity — so you can evaluate a corridor in minutes instead of days.