Marlies Vanhulsel

Tracking household routines using scheduling hypothesis embedded in skeletons

This study addresses complex daily activity-travel routines of households with young children and their proper representation in a computational process model of travel demand using family skeletons expressed as family sequence patterns. Building on qualitative interview research findings, an a priori classification of family types is defined according to the distribution of care and work responsibilities in the household on a typical weekday. Enriched census data are examined to calculate the share of each family type in the region of Flanders in Belgium. Next, individual activity-travel sequence patterns are drawn for children and adults. Finally, these individual sequences are combined to family sequence patterns, yielding a concise representation of skeletal information in activity-travel patterns of household members and their interrelationships. This process is tested and the method offers a promising approach to both household activity-travel analysis and travel demand modelling.

Is Driving 1 km to Work Worse for the Environment Than Driving 1 km for Shopping

One of the measures that is promoted in order to improve the air quality is the decrease of vehicle mileage. However, there are different reasons to assume that not every kilometer driven by car yields the same impact on air pollution nor on the exposure of people. For instance, some trips are driven at high speeds on highways, while others are driven at relatively low speeds in urban environments. This will have an impact on the resulting emissions. Furthermore, emissions exhausted during the night will have a larger impact on the ground-level concentrations than emissions exhausted during the day, due to the higher atmospheric stability. And another aspect is that emissions produced in cities will affect a larger population than emissions in sparsely populated areas. These and other aspects are examined in this chapter. Analysis of the results per trip purpose shows that driving 1 km to work increases the pollutant concentrations about 1.3–1.4 times more than driving 1 km to go shopping, mainly due, but not confined to, the time of the day at which the activity is performed.