Smartphone Based Travel Diary Collection: Experiences from a Field Trial in Stockholm
Andreas Allström, Sweco Society, Ida Kristoffersson, Sweco Society, Yusak Susilo, Royal Institute of Technology
A smartphone app for travel data collection has recently been compared to traditional methods in a field trial in Stockholm. Results show that detailed data was collected and that most users found traditional methods just as intrusive as the app.
Currently, there is a great need for new methods to collect travel data. Traditional methods have considerable drawbacks and, at the same time, the models used to analyse the transport system require more and more detailed and high quality data. The response rate of traditional travel diaries has also declined significantly in Sweden the last decade.
An alternative method that stands out as very promising is to capture raw data from devices that can use any positioning technology (e.g., GPS, WiFi positioning, GSM, etc.), followed by transforming the raw data into meaningful travel data. Since most smartphones are equipped with various sensors that can be used to determine the location of the smartphone, and since smartphones are integrated in the daily life of most people, they provide an unprecedented opportunity for large-scale travel data collection. This method has a great potential to solve the problems related to the estimation of distance/travel time, geographic coding of departure/destination locations and forgotten trips. It will also provide a more detailed and extensive data set, something that is essential for the next generation of transport models.
In a recently completed research project funded by the Swedish Transport Administration the feasibility of replacing or complementing the traditional travel diary, with a suite of tools that make use of smartphone collected travel data has been studied. The advantages and disadvantages of the traditional method and the proposed method were studied. For a fair comparison, both methods have been tested in parallel, i.e., in the same city, at the same time, and with the same respondents. The design of the traditional travel diary used for comparison, for example the definition of a trip, modes and purposes to choose from, was based on the Swedish National Travel Survey.
To achieve the objectives of the project, MEILI, a system that consists of a smartphone application for capturing the movement of users and a web application for allowing the users to annotate their movement, has been deployed. MEILI has been tested and evaluated in both a small pilot and a larger field trial, although in different development stages.
The recruitment of respondents is a critical phase for traditional travel diaries and, as expected, this was the case also for the smartphone based method. A lesson learnt was that it is important to simplify the registration process as much as possible. Recruitment for the field trial was made in conjunction with a traditional travel diary sent out to 130 000 people in Stockholm County in September/October 2015. There was a text at the end of the advance letter and also a possibility to enter one’s e-mail address at the end of the web-based travel diary. In total, 1559 people showed interest to participate in the field trial, most recruited from the web-based travel diary (only 30 people from the advance letter). In the end, 495 signed up for the field trial and out of the users who signed up, 431 responded to the travel diary and 293 managed to collect data using the smartphone application. A follow-up survey was sent out to the users after the field trial.
In total 2142 trips were collected and annotated by 171 users in the field trial. 51 of the users annotated trips covering more than a week. Inference algorithms supplied the user with suggestions of trip purpose, activity location, mode and transfer points. Thus, the users were only required to approve and/or correct/edit the given suggestions whenever necessary.
Besides rare problems with the installation and registration, the smartphone application functioned as expected for the majority of the participants. The solution proposed for overcoming battery limitations worked as expected and the majority of the users did not experience the battery consumption as a problem. Furthermore, the users rarely turn off the application due to integrity issues and the majority of the users found the traditional travel diary just as intrusive as the smartphone application. The main problem for several users, both in the pilot and in the field trial, was the annotation process and the website component of MEILI.
The experiences from the field trial shows that a smartphone based travel diary collection is a very useful complement to traditional travel diary collection methods since it appeals to a different age group and collects more detailed travel data.
Association for European Transport