The Nantes Chronobus Project

The Nantes Chronobus Project


Garrigue Damien, Nantes Metropole


The Chronobus project combines a low cost (1M€/km) but efficient and innovative infrastructure project with a high level of service. The results are surpassing the expectations.


The greater Nantes is a local authority bringing together 24 towns and accounting for nearly 600 000 inhabitants.

In 2009, the main public transport infrastructure was composed of 3 tram lines and 1 Busway line (a tram- like bus). To face the growth of the conurbation, it was necessary to continue the development of the network despite the difficult economical context.

Two decisions were taken:
- Removal of public transport services with low demand: economy of 1M kms/year
- Creation of a network of 10 bus lines with a high level of service: the Chronobus project with the injection of + 2M kms/year on the bus network.

The first phase of the Chronobus project was then launched: 70 km network on 7 lines (4 lines commissioned in 2012 and 3 in 2013) with large operating hours (from 5 a.m to midnight), high frequency (from 5 to 8 minutes at peak and from 8 to 12 out peak) and a permanent service all year long.

In terms of infrastructure, even if the Chronobus does not run on a specific lane all along its route, everything was done to ensure its efficiency: treatment of all crossroads (creation of roundabouts or priority at traffic lights), bus stops (used as tools to regulate traffic and provide accessibility for all), parking reorganisation (to avoid disturbing buses) and creation of bus lanes in congested areas. Everything was done to encourage the use of alternative modes (pedestrian paths, cycle lanes, bus priorities,...) and to constrain general traffic.

Some innovations were developed in terms of bus insertion:
- Traffic plans, with traffic restrictions:
 a low traffic area in the city centre restricted to pedestrians, bicycles, public transport and some motorized vehicles (residents, deliveries, taxis ...)
 a temporary bus lane at evening peak hours in two suburban cities;
- Central single bus lanes, used in both directions with driver checking;
- “Traffic calming stations” facilitating bus docking and preventing traffic from over taking the bus;

A large consultation was made with citizens to explain the project (more than 70 public meetings). The flexibility of the bus as a mode of transport occasionally permitted to adapt the project to local needs. Wide communication about the new supply was made and a light branding was developed for buses and bus stops.

The first results are very encouraging:
- The expected demand (around 70 000 passengers for the 7 lines) has been surpassed: more than 80 000 passengers per day after only a few months of service with ridership still growing. Chronobus lines carry 60% more passengers than previous bus lines with only 70 M€ investments (1 M€/km)
- The reliability is very good (punctuality rate from 82% to 93%).

Some adjustments are still needed but they are in the process of being resolved. The main issue comes from the augmented ridership, resulting in the need to increase the capacity of vehicles in the future and to purchase more articulated buses to follow the rise in the number of users.

An in-depth evaluation is in progress determining the impact of the project on mobility habits, the use of land and public spaces and the efficiency of new tools developed. It will be completed by the end of 2014. In particular, large-scale innovative surveys will be carried out in June 2014, with the support of the State, to determine more specifically which part of the service has affected the choices made by the users. The results will be available for the ETC 2014 presentation.


Association for European Transport