Citation

Bonsall P. Transp. Policy 2009; 16(6): 306-314.

Copyright

(Copyright © 2009, Elsevier Publishing)

DOI

10.1016/j.tranpol.2009.10.002

PMID

unavailable

Abstract

Personal travel planning (PTP) involves providing people with tailored information and assistance which might persuade them voluntarily to increase their use of sustainable modes while reducing their dependence on the private car. The exact method of identifying the recipient's needs varies, as does the range of the information and assistance provided. Impressive results have been reported in terms of changes in behaviour but there remains some scepticism about the reliability of the data used to estimate changes in behaviour and about the shortage of independent assessments. This paper summarises evidence and opinions on the robustness of the published results of PTP campaigns and concludes that, although the prominently published results show a degree of consistency, serious questions remain about the reliability of the methods used to produce these results and about the possibility of systematic bias. It is argued that the possibility of systematic bias undermines the weight that would otherwise be given to the consistency in published results. It is suggested that future evaluations should put more weight on independent and objective monitoring of effects but that it is unrealistic to expect any affordable evaluation to yield a robust, transferable and incontrovertible result.