How this works
These are modeled estimates, not live measurements. Nothing here listens to a microphone. The map is built from OpenStreetMap features and typical daily patterns, so a lawn mower, a barking dog, a storm or a detour won't show up (except Ohio DOT traffic alerts, below).
Noise sources. Roads by class (adjusted for speed limit and lanes when tagged), railways, airports and helipads, truck stops, industrial and commercial areas, schools, daycares, colleges, bars, nightclubs, restaurants, drive-throughs, stadiums and sports fields, churches, hospitals and fire stations (sirens), construction, parking lots and fuel stations. Quiet places: parks, woods, cemeteries, nature reserves, water and libraries.
Levels are relative to a typical weekday midday. Each source starts at its usual weekday-noon level. Every other hour is an adjustment up or down from that midday level: quieter nights, people waking around dawn, morning and evening rush, school drop-off and pick-up, evening nightlife (loudest Friday and Saturday), Sunday-morning church bells, weekday industrial shifts and so on. Road traffic adjustments use the FHWA hour-of-day and day-of-week shares of traffic. The other patterns are typical-schedule assumptions, not measured data.
Choose the spot and the radius. The map starts at your location (or a default spot in western Ohio). To model somewhere else, tap Pick a spot on the map and then tap the map, drag the blue dot, tap the map and choose Move center here, or right-click / long-press the map. The radius slider sets the circle from 1 to 5 km. Larger circles use larger cells so the page stays fast: 30 m cells at 1 km, about 40 m at 2 km, 55 m at 3 km, 65 m at 4 km and 75 m at 5 km. The link in the address bar keeps the spot and radius, so you can share it.
Sound math. For every cell inside the circle, the sound energy of all sources is added up. Roads and railways spread as line sources, about 3 dB quieter for each doubling of distance. Point sources such as a bar or a school spread at about 6 dB per doubling. Soft ground and air take a little more off over longer distances. Being inside woods, a park, a cemetery or near water gives a small bonus of 1 to 3 dB. Buildings, hills and noise walls that block sound are not modeled, so sheltered spots are often quieter than shown.
Live Ohio traffic alerts (on by default). In Ohio, the page also asks the Ohio DOT's OHGO public API for active construction and work zones, incidents (crashes, closures, special events), dangerous slowdowns and travel delays within about 6 km (more for a larger circle), refreshed every 3 minutes. These show as orange markers and in the "Unusual traffic now" list. Only when you're viewing "Now", road-traffic noise near each item gets a small, labeled bump on top of the modeled level: +3 dB for a dangerous slowdown or heavy delay (5+ minutes, or under 60% of normal speed), +2 dB for a lighter delay, +3 dB for a crash, disabled vehicle or special event, +4 dB for a crash or other incident that closes lanes or the road, +2 dB for other incidents, +4 dB for construction with lane or road closures during usual work hours (7 AM–7 PM; +2 dB outside them) and +2 dB for other active construction during work hours (none at night). The full bump applies within 60 m of a mapped work-zone or closure line (fading to zero by 250 m) or within 200 m of a point-only item (fading by 500 m). Only items whose location or mapped line is inside the circle you picked (1 to 5 km) change the levels; farther items are listed and mapped only. Walkway, sidewalk and trail closures get no bump. Where items overlap, the largest bump wins; they aren't added. Other hours and days never get the bump. These are rough adjustments for queues, idling, braking, sirens and equipment, not measurements. Turn the switch off to see the plain model. OHGO covers Ohio only.
Check against federal data. When it's available, road, rail and air levels are scaled to match the US DOT/BTS National Transportation Noise Map (2022, 24-hour average) near roads, by at most ±6 dB.
Labels (dB(A), one-hour average): Very quiet under 40 · Quiet 40–47 · Moderate 47–55 · Busy 55–63 · Loud 63 and up.
Holidays, school breaks, special events, wind and weather aren't included. Public or private access comes from OpenStreetMap tags and may be missing or out of date, so obey posted signs and hours.