The maps below show the same neighborhoods assessed three different ways: the peak loudness of each overflight (what you actually hear), the total sound energy of a pass, and the 24-hour averaged level the FAA uses to decide whether noise legally “matters” (DNL). Switch between them and the same homes can look loud or quiet depending only on which measure you choose.
You can compare today’s departures and arrivals against the proposed BRGHT departure, and see honestly who would get relief, who would see little change, and who would bear more. The analysis shows all three — it does not hide the homes that come out worse.
Start on the “How to read” view (it opens there by default). It explains the three measures in plain language before you dive into the maps. Each map has its own legend showing how many homes fall at each level.
A note on the maps: the street basemap loads from a public map service. If you opened this from a shared file and the map tiles didn’t appear, viewing it here on truenoise.org resolves that — the data and the analysis are unchanged either way.
Aircraft noise was recorded at a community-operated sound meter that meets an international precision standard (IEC 61672 Class 2). Each overflight is captured as a series of readings tied to the specific aircraft, its altitude, and its distance — so every level is anchored to a real, identified flight, not an assumption.
To estimate noise at homes across the corridor, we measured how noise fades with distance using hundreds of recorded departures, then applied that measured falloff outward from the flight path. Homes themselves come from the county’s official address records, checked against Census housing counts, so the population figures reflect actual residences.
The full methods — parcels, addresses, geocoding, flight-path reconstruction, measurement, and the propagation model — are documented with citations in the methodology paper linked below.
The mapped area is not arbitrary, and it is not the edge of where aircraft are heard. Its shape follows the proposed BRGHT departure track — the straight climb corridor running southeast along Route 97 — because that is the flight path this analysis evaluates. The boundary is the measured 62-decibel contour drawn around that track: the line beyond which our model says departure noise drops below the level this analysis is prepared to stand behind. It is also the area our measurements and flight-track records actually cover. Inside the boundary we have a defensible noise level, a specific proposed route, and the data to support both.
We make no claim about locations outside the boundary. Homes beyond the line are not “quiet” and are not being dismissed — they are simply outside the area this particular analysis maps and makes claims about.
We cannot place a microphone at all 9,240 homes. Instead, we measured at one carefully calibrated location and recorded how loud each of hundreds of real overflights was — and, crucially, how the noise fades as the aircraft gets farther away.
Once you know that pattern — verified against real flights, not assumed — you can estimate the level at any home from its distance to the flight path, the same way a thermometer reading plus a known cooling rate lets you estimate the temperature a few steps away. The estimate is strongest near the receptor and the flight path, and we are most cautious toward the edges of the corridor, where distances are greatest. This is estimation grounded in measurement — well-informed, and honest about its limits.
Aircraft noise on the ground depends not on how far away the plane is horizontally, but on the slant range — the straight-line distance from the aircraft to your home, which includes how high it is. Drag the altitude below and watch what happens to the noise and to the 62-decibel reach.
This is the real relationship used in the analysis (measured attenuation, K ≈ 1.2). Because the BRGHT departure climbs as it proceeds, aircraft are higher over neighborhoods farther along the track — so the 62-decibel corridor is widest near the start of the climb and narrows as altitude builds. Higher aircraft push the numbers down; a lower-than-modeled climb would push them up and widen the corridor. The mapped boundary reflects the modeled BRGHT climb profile along the Route 97 corridor.
The BRGHT proposal turns aircraft a little later, over parkland instead of over homes. The question is whether they are high enough by then. This shows what departures actually reach in practice today, from recorded flight tracks. Drag the turn point to read the altitude today’s departures reach there.
Reading it: today’s turn happens low — around 2,450 ft at 3.05 nm, while aircraft are still climbing hard. The altitudes shown are what today’s departures actually reach at each distance; a BRGHT track is a projection, not a flown route, so these serve as evidence of what is achievable, not a measurement of BRGHT itself. They understate rather than overstate the case: deferring the turn removes the early bank that robs climb, so a BRGHT departure would if anything climb better. Today’s departures already reach a median of about 4,250 ft near the BRGHT turn distance, climbing here at a median of ~1,920 ft per minute (nearly half exceed 2,000). The current low turn holds aircraft down; it is not a limit of what they can do.
On the numbers: The standard modeled climb profiles (FAA AEDT / SAE AIR-1845 Aircraft Noise and Performance database, manufacturer defaults) assume more conservative climb rates, roughly 1,000–2,100 ft per minute depending on type. The altitudes shown here are not modeled projections — they are the altitudes today’s departures actually reach, from 526 recorded BWI departures (19,287 track points, early August 2026). In practice, as with the noise measurements, real performance exceeds the conservative modeled default. The modeled standard is a floor, not a ceiling. (The BRGHT track itself is a projection; these recorded altitudes are evidence of what aircraft here already achieve.)
These maps show the same aircraft noise three ways.
The loudest moment of each overflight — what interrupts, wakes, makes you look up. The lived experience.
The total sound energy of a whole pass — loudness and duration together. What DNL is built from.
Energy averaged over 24 hours, every day of the year. The FAA threshold is 65.
Frames differ, too. The current maps show absolute level; the proposal maps (BRGHT, WARYN) in the Peak and Energy groups show effect — relief, no change, or added burden vs today’s total. The DNL group shows absolute DNL against the 65 threshold for every scenario.
The point the DNL maps make: not one home in any scenario reaches DNL 65 — the level the FAA uses to decide whether noise matters. The very neighborhoods that glow red on the Peak maps — jets at 70–80 dBA, dozens of times a day — sit entirely below the line. The burden is real and measured; the metric simply does not register it. Choose a map to explore.