The Rome councillor responsible for traffic, Mario Di Carlo, has announced that measures will soon be taken to discourage the entrance of big four-wheel-drive vehicles into the city centre. The vehicles, which take up more parking space than an average car, are also said to be partially responsible for an increase in atmospheric pollution. Di Carlo hopes to be able to alter the system of issuing permits for the historic centre so that owners will pay according to the size of their vehicle. The measures may come into effect at the beginning of 2005.