The network
What is on the wire right now
Relay is a network rather than a database, so the only useful way to describe it is to show what it is carrying at the moment you ask. This page is rendered per request against the production API, with the same credential an integrator holds.
- 8
- events live
- 16
- areas polled
- 8 km
- radius per subscription
- 2
- types represented
Two sources, one envelope
A consumer integrates once. What varies between an incident declared by the national road operator and one published by a connected fleet is a single field — everything else about reading them is identical, which is the entire reason a neutral trunk is worth building.
source_kind: public
The French national road network
Published by the road operator in DATEX II under Licence Ouverte 2.0, polled continuously and mapped into the Relay vocabulary. Two levels of it: the coarse type a client filters on, and the finer subtype it refines with — a lane closure and a broken-down vehicle are not the same incident and the wire says so. Each row carries its licence and the moment the SOURCE last revised it, beside the moment our sweep last saw it.
source_kind: network
Everything published by participants
A telematics box deriving a queue from a prolonged stop, an app relaying a driver’s report, a suspension sensor calling a pothole. These are the events an operator’s feed structurally cannot contain, because nobody with a camera on a gantry can see them. They arrive in the same envelope and are subject to the same quorum: other vehicles confirm them, and enough denials clear them.
The distribution, right now
Counted across 16 discs on the national road network, deduplicated where they overlap. A national picture is an assembly of small discs — that is what the geohash index answers in constant time, and it is the same shape a subscriber queries in.
- Stopped vehicle7
- Object on road1
Where the discs are
The sixteen were chosen by measurement, not by population: what matters is how many events are ALIVE in a disc when somebody looks, and an event’s time to live is minutes to hours. The Marseille ring and the Nantes périphérique are the two densest places in the country on this feed; the Rhône corridor is thinner than its traffic suggests.
- Paris
- Marseille
- Nantes
- Lyon
- Lille
- Bordeaux
- Toulouse
- Strasbourg
- Rennes
- Montpellier
- Rouen
- Nice
- Grenoble
- Reims
- Orléans
- Clermont-Ferrand
By severity
- high0
- medium8
- low0
- not stated0
Severity is optional on the contract, and an absent one is never guessed at. A publisher who does not grade an incident says so.
Coverage grows one connector at a time
Every extension of the network is the same shape of work: a source is mapped into the vocabulary once, and every existing integrator receives it without changing a line. That property is what makes coverage a schedule rather than a rewrite.
- Connected
The French national road network
The state feed, in DATEX II, mapped to the two-level vocabulary. Both fields a client reads for provenance — the licence and the upstream revision time — are carried through rather than flattened away.
- Per operator
Concession motorways
The densest traffic in France is run by concession operators and published separately. Each one is a connector against the same contract; what it costs is a mapping table and a poll cadence, not a change to anything already integrated.
- Per country
The rest of Europe
DATEX II is a European standard with national dialects and national location tables, so a second country is a real connector rather than a configuration flag. The consumer-side cost of a new country is zero: the vocabulary does not change, so a client written today reads Belgium the day it is connected.
- Continuous
Participants
Every organisation that publishes widens coverage in the one dimension no feed reaches — the events only a vehicle can witness. This is the half that compounds, and it is why publishing is free.
Nothing here is staged
The figures above came out of the production API during this page render. You can make the same calls.