The CSTB provides its expertise to car and train manufacturers and equipment manufacturers, for every aspect, from the issues surrounding aerodynamics combined with driving in rain or snow, to the health and comfort of passengers. The CSTB also works more generally with the stakeholders of development on issues involving the integration of systems of transportation into their environments. Its expertise is based on its skills and experimental resources applied to a systemic approach, airflow, acoustic impact and the quality of ambient conditions in confined spaces (acoustics, quality of ambient conditions, lighting and vibrations) developed within its benchmark fields in construction and urban development.


Our services

  • Weatherproofing of the vehicle interior and of sensitive zones under the hood
  • Optimization of water intake in the engine's air intake lines
  • Display and measurement of water film thicknesses on bodywork and windows
  • Windshield wiping systems up to 250 km/h
  • Droplet deposit by image processing, sensitivity of rain sensors
  • Analysis of two-phase flows under the hood
  • Development of databases on the behavior of liquid films and two-phase flows
  • Optimization of competition or convertible vehicles
  • Behavior of trains in severe weather conditions (rain, snow and dust storms)
  • Behavior of trains in crosswinds (aerodynamic loads in models (scale from 1/5 to 1/50) in simulation
  • Crosswind approval in compliance with EN14067: level surface approach, single ballasted track and embankment
  • Aerodynamic optimization of appendages, including pantographs


Using an experimental approach:
  • simulation of all types of rain up to 140 km/h, wind and snow (dry or wet snow) and snow pack.
  • rainwater seeding with UV reagent to visualize the flow of water on bodywork and windows.
  • simulation of driving in rainy weather, reproducing a “wake effect” droplet size and shape
  • Snow generation: adjustment of the generation parameters using YORK snow canons. Testing the liquid water concentration of snow particles by modulating the airflow and the position of the snow-making machines.
  • Snow pack reproduction, i.e. “snow-covered roads” (surface area: 200m2) by superposing layers of variable densities.
  • Image acquisition and processing: special non-intrusive method for measuring the thickness of films of water on vehicles.
  • Visual displays of flows
  • Analysis of wakes by Particle Image Velocimetry (PIV)
Using a digital approach:
  • Digital simulation of two-phase flows
  • Commercial and open-source codes for CFD: Fluent, OpenFOAM, Code_Saturne
  • Tools for meshing and post-processing data: ANSA, ANSYS Workbench, ParaView

Technological platforms


Quality of indoor ambient conditions and integration into the environment


Our services
  • Prevention of noise pollution and simulation of soundscapes close to surface transportation systems (roads and railways)
  • Design of innovative transportation noise protection systems
  • Characterization of the acoustic quality of the interior of a vehicle: intelligibility and noise transmission between the interior and exterior of the vehicle
  • Rendering of realistic soundscapes, including transportation sounds
  • Digital simulation of noise exposure
  • Sound rendering
  • Synthesis of transportation noise: driving, internal combustion engines and reactors
Internal tool developed by the CSTB:
  • MICADO: prediction of the effects of acoustic diffraction.
    MICADO is calculation software based on the Boundary Element Method (BEM), dedicated to precisely predicting acoustic propagation close to obstacles of randomly complex shapes and sizes and made of ordinary materials.
Software developed and marketed by the CSTB:
  • ICARE: 3D acoustic simulation in complex environments.
    ICARE is a simulation tool of acoustic propagation using asymptotic methods in complex 3D environments. This tool can be used for optimizing the acoustics of a performance hall and predicting intelligibility in vehicle interiors or congested spaces.


Our services
  • Assessment and optimization of artificial lighting systems for visual comfort in vehicle interiors or in the urban environment
  • Optimization of the energy consumption of external and internal lighting systems (in vehicle interiors) Methods and tools
Internal tool developed by the CSTB:
  • PHANIE: prediction of lighting environments.
    PHANIE is physical lighting simulation software, capable of processing highly complex scenes. Right from the design phase of a room, a building, or a vehicle interior, this software can define and visualize lighting scenarios depending on multiple parameters: architecture, natural lighting sources and climate, lamps and light fixtures and type of materials.

Indoor air quality

Our services
  • Analysis and monitoring of airborne contaminants (biological and physico-chemical)
  • Assistance with developing and assessing technological solutions for air purification, microbiological decontamination and indoor air quality for vehicle interiors
  • Large-scale measurement campaigns (regional / national)
  • Static analysis of exposure databases
  • Measurement campaigns in full scale controlled environments
  • On-site expertise: ventilation/chemical pollutants/micro-organisms
  • Digital simulation of ventilation and hygrothermal aspects
  • Laboratory measurements of products: emission/adsorption/reactivity of pollutants
Technological platforms
  • assessment of the action of microorganisms
  • applied virology
  • physics of aerosols (particulate emission of products)
  • bacteriology and mycology
  • assessment of the emission of volatile organic compounds


Our services
  • Study of the propagation of vibrations from ground transportation
  • Prediction of structure-borne noise
  • Experimental characterization of railway vibration sources
  • On-site measurement of the movement of foundations
  • Vibration analysis of sites (upstream assessment of the vibration risk)
Internal tool developed by the CSTB:
  • MEFISSTO: vibration propagation in the ground and in structures
    MEFISSTO is software for calculating the propagation of vibrations in the ground and structures. It is based on the finite element method (structures) and the boundary element method (propagation in the ground). For example, it can be used for sizing systems for reducing the vibrations transmitted to buildings or to predict surface vibrations due to the passing of a train through a tunnel.