Panel surveys track the same individuals over a series of time points to uncover how travel behaviours evolve over time. With increases in computing power and electronic data storage, larger scale panel data sets like the British Household Panel Survey become available. These panel analyses confirm:

Lifecycle effects: e.g. Household car ownership is observed to increase as the head of the household reaches the age of 50 and thereafter declines (mirroring changes in the household structure as young children reach driving age and then leave home)

Asymmetric effects: e.g. Household car ownership is found to be more likely to increase following an increase in income than it is to reduce following an equal and opposite reduction in income. This indicates that car oriented lifestyles may become entrenched following the acquisition of a car.

State dependence and stability: Travel behaviours are observed to be stable (unchanging) and state dependent i.e. The travel behaviour in a previous time period is a good predictor of the travel behaviour in the current or a future time period.

A link between life events and behaviour change: This stability in travel behaviour is observed to be more likely to be disrupted around the time of a major life event like employment changes or residential relocations.

Key References

Dargay, J. and Vythoulkas, P. (1999) Estimation of a dynamic car ownership model: A pseudo-panel approach. Journal of Transport Economics and Policy. 33 (3), pp.287-302.

Hanly, M. and Dargay, J., (2000) Car Ownership in Great Britain - A Panel Data Analysis.London: University College London.

Dargay, J. (2001) The effect of income on car ownership: evidence of asymmetry. Transportation Research Part A. 35 pp.807-821.

Dargay, J. (2002) Determinants of car ownership in rural and urban areas: a pseudo-panel analysis. Transportation Research Part E. 38 (5), pp.351-366.

Dargay, J. and Hanly, M. (2007) Volatility of car ownership, commuting mode and time in the UK. Transportation Research Part A. 41 (1), pp.934-948.

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