which was 30 sec, battery depletion was a serious problem in this study. As their application
consumed the battery of the mobile phone extensively and with a fully-charged battery they
just could collect the travel diary of respondents for just 3-4 hours. Moreover, respondents
had to neglect some of their calls and messages, because the software used by (Ohmori, N,
Nakazato & Harata) prevented the user from making phone calls or sending emails or text
messages while the tracking application was running. It would be predictable that due to
these limitations respondents might alter the real travel behaviours, as they probably
reduced their travel because of the limited battery life of the phone, and also reduced their
communication with others since they could not place phone calls, text message or email
while the tracking application was active (Gonzalez et al. 2010). From a surveyor‟s point of
view, this is not desirable since the observed travel behaviour might be biased and don not
reflect the real travel behaviour that would have otherwise occurred