A fairer balance of noise across the BWI 15R departure corridor
What you’re about to see
The two maps below show the single-event peak sound level — the loudest instant of one departure overflight, in A-weighted decibels (dBA) — for every home in the corridor. Peak is what interrupts speech, wakes a sleeper, and makes you look up: the lived moment, not a 24-hour average.
One map shows today’s 15R departures; the other shows the same corridor under the proposed WARYN-BRGHT procedure. Both use the identical dBA scale, so you read the change by switching between them — a home’s dot in a cooler band is at a lower peak level under the proposal, a warmer band a higher one. Each map’s legend counts how many homes fall at each level.
One assumption to state plainly. This comparison turns on how today’s 15R departures actually fly. In the measured tracks, about 79% curve west after takeoff, and the relief shown here is WARYN-BRGHT moving those departures southeast instead. That west-curving majority is measured, not assumed — but it has not yet been independently ground-truthed against a full operations record, and it drives the entire west-relief / southeast-increase split. If the real share differs, the balance shifts with it.
Start on the “How to read” view (it opens there by default). These are screening-level estimates from a measurement-grounded model — the proposed route is projected, not flown, and per-home values carry about ±7 dB of uncertainty, so the honest signal is the pattern of where exposure shifts, not any single home’s exact number.
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.
The method, in plain terms
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.
- One metric, the one that’s felt. Single-event peak dBA — the loudest moment of each departure.
- Measurement-grounded. A propagation law fit to hundreds of recorded departures, draped along the measured climb.
- Today vs the proposal, one scale. 15R as flown today against the projected WARYN-BRGHT track, read off the same dBA scale.
- Screening-level, stated plainly. Projected figures, about ±7 dB per home — read the corridor-wide pattern, not single homes.
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 boundary, and how far the estimates reach
Why the maps stop where they do
The mapped area is not arbitrary, and it is not the edge of where aircraft are heard. It now follows both departure paths this analysis compares — today’s 15R track, which curves west after takeoff, and the proposed WARYN-BRGHT track, which holds southeast along Route 97 — so the homes that would get quieter and the homes that would see an increase are both on the map. The boundary is the 62-decibel peak reach drawn around each track: the line beyond which the model says single-event peak noise drops below the level this analysis will stand behind, and the area our measurements and flight-track records actually cover. Inside it we have a defensible level, two specific tracks, 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.
How we estimate noise we didn’t measure at every home
We cannot place a microphone at all 33,206 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.
Altitude, slant range, and why the boundary is shaped the way it is
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.
How high aircraft actually climb — and why deferring the turn works
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. 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.)
The interactive maps
Peak noise: today vs WARYN-BRGHT
Two maps, one measure. Each shows the single-event peak sound level — the loudest instant of one departure overflight, in A-weighted decibels (dBA). Peak is what interrupts speech, wakes a sleeper, and makes you look up: the lived moment, not a 24-hour average.
Today’s departures shows the 15R corridor as flown now. WARYN-BRGHT shows the same corridor under the proposed procedure. Both maps use the identical dBA scale, so you read the change by switching between them: a home in a cooler band is at a lower peak level under the proposal, a warmer band a higher one. Each legend counts how many homes fall at each level.
Screening-level. These are projected figures from a measurement-grounded model — the WARYN-BRGHT route is notional (not flown), today’s line is the measured 79%-majority west-curving 15R track, and each home carries about ±7 dB of uncertainty. Read the pattern of where exposure moves across the corridor, not any single home’s exact value. Choose a map to explore.
The two maps, as numbers
The maps above show the same 33,206 homes twice — once under today’s 15R departures, once under WARYN-BRGHT, on one dBA scale. These two tables state that comparison numerically, so the arithmetic is done for you. The first counts how many homes fall in each peak-level band under each procedure. The second groups homes by how much their own single-event peak changes between the two.
| Single-event peak | Today | WARYN-BRGHT | Difference |
|---|---|---|---|
| <55 dBA | 879 | 4,501 | +3,622 |
| 55–60 | 3,492 | 5,317 | +1,825 |
| 60–65 | 10,019 | 11,627 | +1,608 |
| 65–70 | 14,512 | 7,210 | −7,302 |
| ≥70 dBA | 4,304 | 4,551 | +247 |
| Total | 33,206 | 33,206 | — |
| Change (WARYN-BRGHT − today) | Homes | Share |
|---|---|---|
| −10 dB or more | 6,717 | 20% |
| −10 to −5 | 6,134 | 18% |
| −5 to −1.5 | 3,921 | 12% |
| within ±1.5 | 7,256 | 22% |
| +1.5 to +5 | 2,652 | 8% |
| +5 to +10 | 5,068 | 15% |
| +10 dB or more | 1,458 | 4% |
| Total | 33,206 | 100% |
Reading the change column. Change is the single-event peak under WARYN-BRGHT minus the peak today, in decibels: a negative value is a lower peak level under WARYN-BRGHT, a positive value is higher. In all, 21,533 homes sit at a lower peak and 11,673 at a higher one; the median change is −1.75 dB. Figures are the full modeled corridor, screening-level (±7 dB, 95%); the two procedures share the runway segment, so near-in levels are identical by construction.
Elementary schools in the corridor
Aircraft noise at school is associated, in a linear, dose-dependent way, with poorer reading comprehension in children (Clark et al. 2006; Stansfeld et al. 2005). Because the relationship is linear and cumulative, a school at a higher absolute noise level has a worse predicted outcome; reducing exposure at the most-exposed school therefore addresses the children with the worst predicted effect (Clark et al. 2006).
The most noise-exposed elementary school in the corridor is Quarterfield, at 74.5 dBA peak today — and it is among the schools WARYN-BRGHT helps most, lowering its single-event peak to 70.9 dBA (−3.6 dB). Because the exposure–response relationship is linear and cumulative, the largest reduction falling on the most-exposed school is where it does the most predicted good. Severn also falls (−3.7 dB, 62.1 → 58.3), while Glen Burnie Park is essentially unchanged (+1.2 dB). Two schools see increases, stated plainly: Rippling Woods rises 64.3 → 68.8 dBA peak (+4.5) and Southgate 59.9 → 63.1 dBA (+3.2). On the same linear, cumulative logic, Rippling Woods’ increase is a real added exposure for 702 children; it ends below Quarterfield’s post-change level (70.9), but it is not zero and is not hidden here.
Why elementary schools. The focus is deliberate, not a selective omission. Reading comprehension is acquired during the elementary years, and the RANCH studies that establish this exposure–response relationship were conducted on children of roughly this age; younger children are the most developmentally vulnerable to noise interference with learning. The same corridor method applies to any school — middle and high schools can be added on request.
| Elementary school | Enroll. | Today | WARYN-BRGHT | Δ dBA |
|---|---|---|---|---|
| Quarterfield | 544 | 74.5 | 70.9 | −3.6 |
| Glen Burnie Park | 555 | 70.2 | 71.3 | +1.2 |
| Rippling Woods | 702 | 64.3 | 68.8 | +4.5 |
| Severn | 458 | 62.1 | 58.3 | −3.7 |
| Southgate | 573 | 59.9 | 63.1 | +3.2 |
Single-event peak dBA, screening-level (±7 dB, 95%), from the measurement-grounded departure model; WARYN-BRGHT is a projected route, not a flown one. The RANCH exposure–response is established on LAeq,16h, a 16-hour average — not single-event peak — so the direction of effect (more exposure, poorer reading) transfers, but the per-decibel coefficient is not applied to these peak figures.
References. Stansfeld SA, Berglund B, Clark C, et al. (2005). Aircraft and road traffic noise and children’s cognition and health: a cross-national study. The Lancet 365(9475), 1942–1949. · Clark C, Martin R, van Kempen E, et al. (2006). Exposure–effect relations between aircraft and road traffic noise exposure at school and reading comprehension: the RANCH project. American Journal of Epidemiology 163(1), 27–37.