The practices and standards of travel behavior data collection have changed significantly over the past decade with the introduction of mobile, location based technology. The use of GPS devices such as loggers has been a great enhancement to the field. However, with the increased ubiquity of smartphones, which come equipped with a variety of sensors useful to behavioral data collection, the possibilities and methods used in data collection are again shifting. These mobile devices offer several exciting opportunities to either collect more data from respondents with a similar amount of burden, or collect previously burdensome data (such as detailing time use by paper and pen survey) with little or no interaction from the respondent. In this paper, an overview of possible sensors is presented, as well as current research efforts in the field. A forthcoming analysis of sensor frequency, battery expenditure and accuracy of detection will also be discussed in the final version of this paper.