Samenvatting
The author believes that current economic activities seriously threaten the environment and life on earth but that this is given insufficient weight at the planning stage. An alternative procedure is described which puts environmental constraints in advance of any planning, development or trend calculation. Entitled 'trendbreach studies', the results show what level of development is permissable in order to save the environment for future generations. A study carried out by this method in 1988 for passenger transport in the Netherlands is outlined. Figures for the neccessary environmental constraints are suggested.