Where does the data come from?

Route and distance

Routes are computed from OpenStreetMap data. Up to 1,500 km we use Valhalla, which also reports toll-free preferences and ferry legs. Longer routes such as Istanbul–Berlin exceed Valhalla's distance limit, so OSRM is used instead and those two features are unavailable.

Country segmentation

The route line is split server-side against Natural Earth 1:10m country borders, so each country's kilometres are priced separately. Border crossings are located by binary search, accurate to roughly 100 metres.

City and town list

The Turkish list is built from OpenStreetMap’s settlement tags: the 81 provinces are kept by hand (for aliases such as İçel and Afyon, and because İstanbul is split into its European and Asian sides), while districts and resorts come from the data. For Europe, more than fifteen thousand places above five thousand inhabitants come from GeoNames; that list is fetched after the page has loaded, so it does not slow the first paint. Each city is shown under the name used in its own country — Wien, Napoli, Beograd — and its Turkish exonym still matches in the search box.

Source: OpenStreetMap (ODbL) · GeoNames (CC BY 4.0) · Last updated: 2026-08-22

Fuel prices

Each country's price is stored in its own currency and converted at display time. Turkey is stored in lira: with a volatile exchange rate, a euro-pegged Turkish price goes stale within weeks.

Source: EU Weekly Oil Bulletin (EU27, pulled by scripts/update-fuel.mjs); everything else hand-maintained — Turkey from EPDK/distributor pricing, the Balkans and Ukraine/Moldova from national sources, all electricity prices from operator tariffs · Last updated: 2026-08-17

Tolls

In vignette countries (Bulgaria, Hungary, Austria, Slovenia, Romania, Switzerland, Czechia, Slovakia) we pick the cheapest vignette that covers the trip. In per-kilometre countries (Serbia, Greece, Croatia, Italy, France, North Macedonia) the motorway share of the route is estimated, and known transit corridors use their published fare. In Turkey an average motorway rate is applied, plus bridge and tunnel fees when the route passes them.

Exchange rates

Rates come from European Central Bank reference rates plus a supplementary source, all normalised to a euro base so no calculation ever mixes base currencies.

Source: api.frankfurter.dev (ECB) + open.er-api.com, normalised to a EUR base · Last updated: 2026-08-22