Cycling accidents in Rennes

The denominator trap

Rennes is a student city with a high level of cycling, and that distorts how the map reads. The areas around the Beaulieu and Villejean campuses, the Vilaine embankments and the city-centre junctions accumulate accidents partly because they carry far more cyclists than anywhere else.

Without exposure data — how many cyclists pass through — a cluster cannot be told apart from an inherently dangerous place. Read the map as a picture of where cycling happens as much as of where it goes wrong.

What the data covers

Only injury accidents that led to police involvement are recorded. Falls without a third party and minor collisions settled amicably are absent, as are near misses.

The severity shown is that of the most seriously injured casualty. Each record gives, where available, the light conditions, the weather, the type of collision and the kind of road.

Frequently asked questions

How many cycling accidents are recorded in Rennes?

Several hundred injury accidents involving a cyclist are mapped across the area covered between 2015 and 2023, a minority of which led to hospitalisation.

Where does this data come from?

From the injury accident reports (BAAC) filed by the police and published by ONISR, via the derived “Accidents de vélo” dataset.

Does a red area mean the place is dangerous?

Not mechanically. It marks a cluster of accidents, which also depends on how many cyclists pass through — and in Rennes, that number is high.

Is the data up to date?

BAAC records are published several years in arrears. The data currently available covers the period 2015 to 2023.

Sources and licences

• « Accidents de vélo » — derived from the ONISR BAAC files, published by Koumoul · data.gouv.fr · Licence Ouverte 2.0

Each dataset and its licence are listed on the Data sources page.