-Reduce number of Vehicles - Urban areas need to set vehicular quotas and issue permits to limit the number of vehicles to control regional traffic congestion and air pollution.
-Improve efficiency of vehicles - reverse the trend to larger vehicles; engineering solutions to emissions of combustion engines. Flex fuel and hybrid cars are a step in the right direction but in small numbers will not have a significant impact on air pollution.
Reduced vehicle use and traffic reform can be a bigger and more immediate remedy for urban air pollution. Improved efficiency of traffic is important. Examples are: dedicated bus lanes and priority for car-pools and vehicles with 3 or more passengers. Traffic can be scheduled to optimize road usage; e.g. commercial traffic at night; large companies can stagger working hours and decentralize administrative operations. Commuting long distances in cars to work needs to be phased out. Single passenger commuting to work should be strongly discouraged.