The consumption of fuel by heavy motor vehicles, both passenger and freight, driven on typical Mexican roads, has a direct influence on pollutant emissions. This fuel consumption strongly depends on driving practices, as has been shown by data gathered in field tests conducted with a large number of vehicles in a variety of driving conditions. So-called 'technical driving', which essentially means an optimal use of the engine speed and torque, has demonstrated substantial savings in fuel consumption and, therefore, is an effective practice for the reduction of pollutant emissions. In this paper, the main results of an extended field study, using the technical driving, are presented.