Optimising a city's transportation system requires insights into the dynamics of urban traffic to understand where, how, when, and to what extent people travel within the city. The rationale behind route selection and the choice of transportation mode are also of importance. The primary source of this data is the travel diary, a tool designed to survey people's transport behaviour. Based on a paper by Maria Sergienko, a master's student of the HSE Faculty of Urban and Regional Development, IQ.HSE examines how people's daily travel can be described in detail and why an automated diary cannot yet completely replace its manual counterpart.
A travel diary is a survey instrument designed to record all of an individual’s travel over a given period in relevant detail. It facilitates the discovery of where individuals and social groups travel, the frequency of their movement, and the routes they take. It can accommodate a range of trips, whether within or outside of the city, regular or infrequent, on foot or using various modes of transportation such as private cars or buses. A travel diary enables the analysis of both local transportation patterns and broader aspects of urban mobility.
Respondents are asked to document the details of their trips from memory, typically at the end of the day. Based on these records, the travel diary makes it possible to examine the reasoning behind the selection of transportation mode and departure time, the purpose and frequency of trips, as well as the distances covered—essentially encompassing all aspects of people's transport behaviour. Furthermore, travel diaries also enable the study of collective transportation behaviour, eg of the entire population of a city or region.
Travel diaries help assess current and forecast future demand for means of transportation across various modes and routes. This enables optimisation of the transport system for greater efficiency and public convenience, as well as the appropriate allocation of rolling stock within the city's network.
In addition, travel diaries reveal aspects such as transport accessibility, the influence of neighbourhood design on residents' transport behaviour, the transportation challenges faced by certain social groups, and the environmental impacts, such as exposure to traffic-related air and noise pollution. Diaries can signal that certain routes and transport schedules are inconvenient for specific groups or that the overall transportation policy could be improved.
Travel diaries can even be used to examine the individual valuation of time—how much a person is willing to pay, eg, to save a minute of their commute. This information is essential for the calculation of potential economic impacts from alterations to the transportation system.
When they were first introduced more than 60 years ago, they did indeed take the form of large notebooks. However, as time passed, methods of record-keeping have evolved from the traditional paper-based, written format to the modern practice of logging information on a smartphone (even audio diaries are available today). This modernisation has largely been driven by respondents' reluctance or inability to allocate significant time to the survey, given that everyone is busy and constantly on the go.
However, the content of travel diaries has remained consistent over the decades and includes the respondent's personal details, the departure and destination points, the purpose of the trips, and so forth. The survey questionnaire can be expanded to align with the particular focus of any given study. Hence, various diary designs are possible.
There are several types:
Stage-based, which focus on a single mode of transportation, encompassing the waiting time both before and during the journey
Trip-based, which capture the entire trip, examining each of the respondent's movements between two distinct activities
Activity-based, which focus on the activity first and then establish the trip details as additional information
Half-tour, in which the respondent describes their travel to the furthest point of the tour, including any interruptions along the way.
Some experts argue that it is time to replace traditional, manually filled diaries with automated versions that can record people's movements autonomously, eg using satellite navigation systems such as GPS or GLONASS. Automated diaries can save time and effort for both researchers and respondents, enabling the collection of substantial volumes of data. They are even suitable for individuals with disabilities which may prevent them from independently filling out a diary.
Moreover, automated formats generally exhibit greater accuracy in capturing specific travel details. Researchers who have used GPS data loggers to gather travel data in personal vehicles suggest that this automatic monitoring can serve as an equivalent substitute for conventional diaries.
They probably shouldn't. The reality is that automatic diaries generate depersonalised data. However, subjective aspects, such as the emotional component of decision-making during trips, eg when selecting a route, are also essential for a comprehensive analysis. Only conventional diaries can capture this kind of information by allowing respondents to provide unstructured responses, much like a qualitative study. A manually filled diary can precisely convey the purpose of the trip, the reasoning behind route selection, and other aspects that automated diaries are still incapable of capturing, despite ongoing efforts to improve their performance.
Now, with the advent of new technologies, digital versions have become available. They reduce the costs associated with distributing physical diaries and retrieving data and allow for a broader sample to be included. However, specific groups, such as senior citizens, might encounter challenges in accessing web-based forms or completing them, thus leading to increased costs for researchers.
There are certain limitations as to the content which can be included in a digital diary, as this format is less flexible and tends to favour closed multiple-choice questions. In this respect, paper-based tools are more versatile.
However, distributing paper-based diaries by post, collecting the data, and then digitising it for processing can be time-consuming and expensive. Hence, many researchers favour digital data collection formats, complementing them with paper-based surveys when needed.
This approach integrates both automated and manual diary completion methods. Respondents can review the automatically populated data and make manual corrections if necessary. The operational mechanism is as follows:
There are two main methods used for generating automated travel diaries: one involves dedicated devices, while the other uses smartphones. Both have their limitations, and each entails substantial costs for researchers. Using a dedicated device necessitates its creation, distribution and retrieval, while a smartphone requires an application to be developed. The latter method is often considered more appealing, as nearly everyone owns a cell phone, and the data collected using smartphones is automatically stored in the system. Dedicated devices, on the other hand, collect more accurate raw data on movements. In any case, systems that combine automated data collection with manual verification offer the most comprehensive information about trips and can be considered optimal.
Yes—these include Future Mobility Survey and Move Smarter. However, MEILI is regarded as the most versatile system, as it integrates all existing travel data collection methods and offers the option to edit them. The parameters captured by the system include the respondent's location, route, trip destination, purpose, and transportation mode (with a selection of 15 modes). The option to segment a trip into stages is also available.
According to empirical studies, this system stands out as a promising alternative to conventional travel diaries in terms of data quality and level of detail. This application offers a cost-effective means of generating information about traffic flows, behavioural patterns, travel times, and more. This approach facilitates the work of transport planners in designing city transportation systems that prioritise people's convenience.
Some people find it tiresome to document all the details of their trips. When filling out travel diaries from memory, respondents may inadvertently omit certain movements or consider them insignificant. Therefore, it's common for the number of recorded trips per person to decrease with each day of diary completion. This is particularly noticeable when diary records need to be maintained for extended periods, such as a week rather than just a couple of days. Undoubtedly, these inaccuracies and omissions can affect the representativeness of the data. Nevertheless, there is evidence to suggest that as respondents become more accustomed to filling out the diary, they tend to do so more accurately and fully over time. This can have a positive impact on the results achieved.
Typically, it is a week. Records maintained over seven days provide a fair amount of information. In contrast to shorter-term records, they offer insights into the behavioural habits and movements of specific social groups, along with information regarding the time and material costs incurred by the respondents. Clearly, a respondent's trips can vary significantly depending on the day of the week in terms of destination, route, mode, and duration, and a seven-day diary will capture this variability. However, some researchers contend that even two-week diaries may be inadequate for fully assessing the variability in transport behaviour patterns.