In this work a quantitative analysis of the risk in the land transport of hazardous materials in Sicily has been executed. Risk calculation has been carried out using the TRAT-GIS code, a software for incidental and environmental risk assessment associated with the transport of dangerous substances and supported by a Geographical Information System (GIS) Results have been collected in a database, the GIS allows to display the risk maps Risk analysis has been made on a regional scale, then some critical points have been analysed in detail Comparisons between different typologies of transport and routes have been possible by means of the risk maps In order to reduce the risk and improve the protection of citizens, some proposals have been analysed in these past years and some of them have been recently realized. In this study other proposals for the optimization of the transport system have been formulated, results have also permitted to evaluate the risk reduction after the future application of the Regional Transportation Plan for the Sicily (C) 2010 Elsevier Ltd All rights reserved