  The vehicular flow in the urban street canyon is considered. The classical
field description is used in the modelling of the vehicular movement and of
gaseous mixture in generic urban street canyon. The dynamical variables include
vehicular densities, velocities, and emissivities: of pollutants, heat and
exhaust gases, as well as standard mixture components' variables: densities,
velocities, temperature, pressures. The local balances' equations predict the
dynamics of the complex system. The automatic control of the vehicular flow is
attained by the sets of coordinated traffic lights. The automatic control is
aimed at minimization of traffic ecological costs by the application of
variational calculus (Lagrange's and Bolz's problems). The theoretical
description is accompanied by numerical examples of computer fluid dynamics
based on real traffic data.
