Radius & footprint

Radius (m)

Position

Mode

You spd km/h Hdg °

GPS status is summarized above the map. Open Settings here to change mode or retry GPS.

Map display

Snap vehicles to static route Draw static route line (GTFS shape) Brake zones Full-screen “Nézz fel!” proximity alert Yellow warning over other apps Heading-up map (autorotate)

Language

Sound alerts (proximity beeps) Safe heartbeat when clear

Safe heartbeat interval s

Default 10 s (0.1 Hz). Does not affect yellow proximity beeps — those still ramp from 1 Hz as vehicles get closer.

Directional audio (stereo pan)

Warning zones (corridor overlap) Red radius m Yellow radius m

Map rings (outer → inner): green dotted ~198 m heartbeat · orange dotted ~110 m warning (Yellow radius) · red dotted ~14 m danger. Corridors only draw inside the green ring.

Vehicle corridor reach Uncertainty horizon s Stopped look-ahead s Front expansion limit m/s Front contraction limit m/s

Controls how far the yellow/red corridor ribbon extends forward from each vehicle (staleness + worst-case braking). Lower = tighter ribbons, fewer false overlaps.

0 means immediate/unlimited. Default expansion is immediate for safety; the 16 m/s contraction limit removes a typical BKK update correction over about 3–4 seconds.

Acknowledge mute — yellow s

Yellow ack silences warnings only. Red danger for the same vehicle still fires until you ack the red card.

Acknowledge mute — red s

Danger downgrade margin m

Danger latch s

User red zone speed horizon s

Red zone radius ≈ Immediate + (your speed × this). Standing → circle at Immediate distance.

User yellow zone speed horizon s

Yellow zone radius ≈ Max center + (your speed × this). Warnings fire when a vehicle corridor intersects these zones.

Severity realert hold s

Mirrored to the native background monitor via the same keys (lajos_mute_*, lajos_danger_*, lajos_severity_*).

Resets warning zones, corridor reach, mute/latch tuning, and user footprint radius.

Stops background monitoring and sound, then closes LAJOS. Reopening the app starts monitoring again.

Show vehicle modes

Backend server

Backend (LAJOS API)

Pick a preset (e.g. Budapest — BKK) or Custom URL. Same host = this page’s origin. The server can set LAJOS_BACKEND_URL_BUDAPEST in .env for the Budapest preset.

Diagnostics

Providers ok: — Errors: — Vehicles: — HTTP: — ms BKK feed age: — Since BKK feed change: — Backend fetch age: — Since backend fetch: — Latest audio: —

Audio trace (WYSIWYG)

Native MODE/BEEP events with timestamps. Compare the latest BEEP time with a screenshot — also on logcat tag LajosAudio.

Loading…

Provider	Mode	Line	Vehicle	Trip	Route id	Lat	Lon	Bearing	Speed

About

LAJOS — pedestrian proximity alerts for Budapest transit.

App version: Loading…
Backend version: Loading…
Backend API: —

License & data

LAJOS is proprietary software owned by Peter Salamon. No permission to copy, modify, or distribute it is granted without a written agreement. Third-party software and data remain under their own licences.

Data sources

Data source: BKK Zrt., CC BY 4.0. LAJOS retrieves and processes the data; BKK does not endorse LAJOS.

Open-source components

LAJOS includes Leaflet (BSD-2-Clause), fflate and Capacitor (MIT), and Android components under their recorded open-source licences.

Packaged notices

Leaflet 1.9.4 — BSD-2-Clause
Copyright © 2010–2023 Volodymyr Agafonkin; © 2010–2011 CloudMade.

fflate 0.8.2 — MIT
Copyright © 2023 Arjun Barrett.

Capacitor — MIT
Copyright © 2017–present Drifty Co.

AndroidX, Android Gradle Plugin, Kotlin, OkHttp/Okio and related Android
components retain their applicable Apache-2.0 or other recorded terms.

Full notices and licence texts are included in the source distribution and
in this application's legal assets.