Although the amount of time people have spent in motion has remained constant since 1950, the shift from feet and bicycles to cars and planes has increased the speed of travel fivefold.[6] This results in the twin effects of wider and shallower regions of social activity around each person (further exacerbated by electronic communication which can be seen as a form of virtual mobility), and a degradation of the social and physical environment brought about by the high speed traffic (as theorised by urban designer Donald Appleyard).