Paris: A1 motorway – road sharing simulation study


2010, updated in 2014


Cerema Centre d’études et d’expertise sur les risques, l’environnement, la mobilité et l’aménagement

SCEP le service connaissance, études et prospective

DRIEA La Direction Régionale et Interdépartementale de l’Équipement et de l’Aménagement Ile-de-France

Paris: A1 motorway - road sharing simulation study


In this road sharing study, SCEP used Aimsun traffic modelling software to define the optimal length and position of the reserved lanes for buses and taxis on the Paris ring road and the section of the A6a serving Orly airport.


The 2010 study by SCEP, DRIEA of the reserved taxi/bus lane on the A1 road was updated in 2014 to analyse the impact of this reserved lane on congestion and travel time for other users on the northbound A6a road from entrance A106, which serves Orly airport, and the Paris ring road in the morning rush hour.

SCEP tested two Aimsun models and compared the results to simulate the effects of reserving a lane for buses and taxis on road A6a, and to predict the consequences for the A6b road running parallel.

A1 Paris reserved lane for bus and taxi

Reserved lane on the A6a

The possible driver behaviours on one route over another depending on congestion caused by the reserved bus and taxi lane on the approach to la Porte d’Orléans were approximated using data and analysis provided by DiRIF. The effect of the project on other road users was evaluated from the A10 in the south up to the ring road in the north.

In its work for SCEP, Cerema has measured vehicle occupancy rates on areas that have good potential for road sharing and measured the proportion of vehicles occupied by one, two or three people. The results have shown the possible benefits of allowing carpooling vehicles on the various section of lanes reserved for public transport.

Further references:

Dedicated issue of the DRIEA “COGITO” journal to the study – Issue nº 10, December 2014 (in French only) Les voies dédiées en Ile-de-France vers une plus grande maîtrise du trafic routier

Paris: A1 motorway - road sharing simulation study