The context resulting from the development of tfansportations and the requirements of a better accoustic confort. Characteristics of the noise: sound speed; accoustic pressure; accoustic diagram; directiveness of the sound; accoustic spectrum. Environment impact of the noise. Comparison of the railway and roadway noise. Most important factors that influence the noise: pavement type; traffic characteristics; traffic intensity and topography of the place. Admissible accoustic levels; level of equivalent accoustic pressure. Noise absorbing walls; dimensions, colour, texture, shape and setting. Reflector and refractive walls. Some solutions - Lenticular - In a rectangular absorlioit box - Reflecting concrete - Small precast pieces - Wooden walls - Transparent walls
