On September 22 of each year a large number of French and European towns reduce the motor vehicle traffic in their city centre. Diffusive sampling of benzene, toluene and xylene during periods of 10 hours was used to characterise the improvement of the air quality due to these traffic restrictions. Despite the short sampling duration the use of diffusive sampling led to results consistent with the reduction of the number of motor vehicles and the measured concentrations of carbon monoxide. While under normal traffic conditions most benzene roadside concentrations measured during the day under low wind speed conditions exceeded the European limit value of 5 ug/m3 , these concentrations decreased to an average of 1.5 u.g/m3 under restricted traffic conditions with only 2 out of 10 measurement sites showing concentrations exceeding the French air quality target value of2 ug/m3 .