How to Track Buses and Trains Live on a Map
▸ Where the dots come from
Most live transit maps are built on GTFS Realtime, an open format transit agencies use to publish vehicle positions as a data feed: this bus, on this trip, is here, now. Agencies publish them for their own apps, and the same feeds power third-party maps. WorldEye's transit layer reads those public feeds directly for 15 metro systems — including Utah's UTA (TRAX light rail, FrontRunner commuter rail and buses), Boston's MBTA, Denver's RTD, Seattle's King County Metro, Austin's CapMetro and Norway's national Entur network.
Tap any vehicle and the popup shows what that agency's feed actually provides: route number and name, the destination headsign, direction, how late or early the trip is running, the vehicle ID, and how old the position fix is. If a feed doesn't publish a field, the popup leaves it out rather than guessing.
▸ How accurate is a live bus dot?
Accurate to the agency's own reporting — which varies. Vehicles typically report every 15–30 seconds, so a dot is where the bus was a few seconds ago, not this instant. Between reports, WorldEye interpolates movement along the vehicle's heading so buses glide instead of teleporting, and the popup's fix-age readout ('updated Xs ago') tells you exactly how fresh the position under your finger is. Late-night and rural routes report sparsely or not at all: an empty map at 3 a.m. usually means the buses genuinely aren't running.
One quirk of the underlying data: some agencies' feeds omit the route on each vehicle and identify only the trip. WorldEye resolves those against the agency's published schedule data, so a UTA bus shows its real route number (and its correct mode — a FrontRunner train is never drawn as a bus) instead of a bare ID.
▸ The road layer next to it: real congestion, simulated cars
Zoom into a city with the traffic layer on and you'll see colored roads and moving vehicles. Be precise about which is which, because WorldEye labels them differently on purpose: the congestion colors are real — live flow data from TomTom, the same class of probe data behind commercial traffic maps. The individual vehicles are simulated: a traffic model that drives plausible cars along the real road network, slowed by that real congestion data. They're useful for reading the rhythm of a road, useless for tracking a specific car — and the on-screen chip says 'VEHICLES: SIMULATED' in exactly those words.
Click a road and the map offers the ground truth instead: the nearest real traffic cameras within about a mile, watchable in the normal camera viewer.
▸ Try it
Open the [globe](/), turn on the transit layer, and zoom to any covered metro — Salt Lake City, Boston, Denver, Seattle, Austin and ten more. The layer panel names the covered systems, and if you pan somewhere without coverage the map tells you that too, instead of showing a mysteriously empty city. Both the transit and traffic layers are free.
▸ Frequently asked questions
Why is my city not covered?+
Coverage needs a public, keyless realtime feed. Some major agencies gate theirs behind developer keys or paid platforms, and a few feeds (New York's NYSDOT, Ohio's OHGO among them) require registration we can't complete for a public map. The panel lists exactly which metros are covered.
Can I track a specific bus to ride it?+
For trip planning, your agency's own app is the right tool — it has stop-level predictions. WorldEye's layer is built for watching a whole network move and checking conditions, with per-vehicle route, destination and delay where the feed provides them.
Are the traffic vehicles real cars?+
No. The congestion coloring is real TomTom flow data; the vehicles are a simulation driven by it. The layer says so on screen at all times.
Try it live on the map.
Everything in this guide runs on WorldEye — the free 3D globe with flights, cameras, satellites, and natural hazards. No signup.