Very interesting notion: “Zahavi’s hypothesis”, i.e. the assertion that, independent of the conditions of passenger travel, individuals’ daily travel time budgets remain constant. An increase in travel speeds would then imply an increase in daily distances travelled, a less dense pattern of urbanisation and an increase in the problems of urban sprawl. While the costs of transport, and particularly time requirements for commuting, have impacts on urban form and city sizes, the statistical problems in the studies on Zahavi’s hypothesis and the lack of attention to what determines firms’ and households’ location choices do not allow immediate conclusions to be drawn on urban policies.
ZAHAVI Y., 1973, « The TT-relationship : a unified approach to transportation planning », Traffic engineering and control, pp. 205-212.