Itinéraire Bis

The cunning bison doesn't follow the crowds! The Itinéraires Bis, simply translating as "alternative routes" is a network of secondary routes designed to take long distance traffic away from congested roads.

The scheme was born following the summer of 1975, where on 2 August the N10 route (a 800km trunk road from Paris towards the Spanish border) was badly congested. At 11am, the autorities reported over 600km of the route was suffering with traffic jams.

The consequence was (naturally) a need to do something about it. And so Bison Futé (Cunning Bison) was born, promoting a network of alternative routes that motorists could take to help shed some of the load onto other routes. Free maps would be provided to provide directions, allowing motorists to skip those notorious bottlenecks.

 

Fast forward to today, and there are nearly 3,500km of Bis routes across France, made up of alternative motorways, trunk routes and better quality secondary routes (often de-trunked roads), chosen to act as relief routes during the busy holiday periods.

They are easily recognisable with their yellow and black icon situated on a yellow panel:

Older signs still exist on many routes, with the yellow and black reversed, and the icon found on a green panel with a yellow border.

When roads are congested, the authorites will activate what is known as the Polomar plan, whereby variable message signs warn of problems further down the motorway and request that traffic diverts via the Bis. The police may also hinder access to the motorway by closing off access points, requesting these motorists use the same alternative route.

Normal and alternative Bis routes to Marseille signposted from the A49

Such routes are permanently signposted, so even when the motorway is quieter, they make for a leisurely drive through the French countryside. Great if you're not too pushed for time!

 

Itinéraires de Substitution

These are another form of alternative routes, marked with a number prefixed with the letter "S". The French equivalent of those strategic diversion routes that the UK signpost with shapes, these are shorter deviations from the motorway that typically bring you back to the intended route one or two junctions further down. They also provide alternative routes around towns and cities.

 Picture credits
 D86 signage  is taken from an original by Chris Zwolle and used under this Creative Commons license
 A49 signage is taken from an original by Tabl-trai and used under this Creative Commons license