SrednaBG

SrednaBG — Your real-time average in Bulgaria's average-speed zones

Bulgaria's average-speed cameras don't fine you for an instantaneous spike. They average your speed between two points and ticket you if that average exceeds the limit. Most navigation apps will warn you that a zone exists, but none of them tell you the one thing that actually matters: what your average is right now, and how fast you can still drive without getting fined.

SrednaBG fills that gap.

Please note: SrednaBG works only within Bulgaria. It covers Bulgaria's average-speed zones exclusively and has no data for other countries.

What it does
As soon as you enter an average-speed zone, SrednaBG starts a precise average-speed calculation based on your GPS position and elapsed time. On a single, glanceable screen you see:
• Your current speed
• Your running average since the zone start
• The maximum speed you can sustain for the remainder of the zone without exceeding the legal average
• Distance and time remaining inside the zone
• The posted speed limit for the zone

If your projected average is about to exceed the limit, the app warns you clearly and in time to do something about it.

Why it's different
Unlike traditional speedometer or radar-warning apps:
• It calculates the math that the camera actually does, not just a static speed reading
• It tells you the highest safe speed for the rest of the zone, so you don't have to overcompensate by crawling
• Zone data is sourced from official BG TOLL listings, cross-checked with TollTracker and verified against OpenStreetMap
• It's offline-first: zones and the map work without a network connection

Built for daily driving in Bulgaria
• Bulgaria-only by design — the app covers Bulgaria's average-speed zones and does not work in other countries
• Offline map of Bulgaria included in the app — no roaming charges, no data costs
• Adaptive GPS polling (frequent inside zones, relaxed elsewhere) to protect battery life
• Audio alerts so you don't have to take your eyes off the road
• Auto-stops tracking after a period of inactivity, so a session forgotten in the background won't drain your battery overnight
• Interface in Bulgarian and English

Free, open-source, no ads, no tracking
SrednaBG is released under the MIT license. The complete source code is public on GitHub. There are no ads, no analytics, and no account is required. The app never sends your location anywhere — all calculations run on your device.

Permissions
• Location (foreground and background) — required to detect zone entry/exit and calculate average speed while the screen is off
• Notifications — to show the ongoing tracking notification while the app runs in the background

Data accuracy and updates
The zone database is refreshed automatically from official sources. Updates arrive as small data files — you don't need to update the app every time a new camera appears.

Feedback and bug reports
The project is community-driven. Issues, suggestions and zone corrections are welcome on GitHub:
https://github.com/demosten-com/SrednaBG

Recent changes:
• New: Trip history — completed average-speed zones are saved on your phone, with your average, top and lowest speed and a speed graph.
• New: "Show on map" — open any past trip on the map, colored by the result.
• New "Not measured" status when the app starts mid-zone and never saw you enter.
• Fixed: false zone entry when driving on a road alongside a zone.
• Fixed: the first word of a voice alert is no longer swallowed.
• Clearer vehicle types, updated map and zone list (now 76 zones).