The link between travel Time Budget and Speed: a Key relationship for urban space-time dynamics

The relationship between travel time budget (TTB) and speed is central to transport economics and allows us to analyze travel behaviour, urban structure and the transport system. Together, this relationship and Zahavi's hypothesis provide a straightforward mechanism that explains the increase in daily travel distances and urban sprawl. However, quantitative analysis (Regression Analysis and Principal Component Analysis) shows that TTBs are only stable at an aggregate level, and the potential of urban speed restriction policies is severely limited at local level.