Public transport (mass transit) is critical to the proper functioning of any city, town or rural area. A range of transit modes offer different capacity opportunities, and therefore the potential for high or low impact on car use. Higher capacity systems cost more to put in, but offer much more potential reduction in total transport costs and greenhouse gas emissions. The social, economic and environmental costs of not having an efficient mass transit system never go away, so it is really a case of stemming these costs earlier or later.

The modal split for freight transport varies greatly by region, and is largely determined by geographical and economic factors. However there is a common trend towards more use of road transport, at the expense of rail and water transport. The latter modes have a substantially better environmental profile, but are limited by longer delivery times and the necessity of pre- and post-haulage by truck, i.e. inter-modal transport. In the logistic chain used nowadays, there are small local stocks and fast on demand delivery is required.