Framed mode choice experiment for analysing commuter behaviour

Lack of travel demand measures to curb private vehicles in the city, leading to the problem of traﬃc congestion in the emerging megacities. Analysis of the problem of traﬃc congestion to commuter travel mode preferences in the city opens up the door for theoretical exploration of the process of traﬃc congestion. The study reports the analysis of the framed ﬁeld experiment to investigate the behavioural responses of commuters. By involving 204 commuters, the research is aimed to investigate the behavioural response of commuters if demand-based non-technical measures are implemented as treatments in the experiment. The two central questions related to this objective are: how do commuter travel mode preferences contribute to urban traﬃc congestion? And, how can this be empirically analysed in terms of the eﬀect of demand-based non-technical measures?

quality consequently fails due to the opportunistic behaviour of some rational commuters, thus leading to a collaboration problem in this phase.
The subsequent increase of additional private vehicles directs the traffic flow from stable to a forced flow (q to q ), that is, the number of vehicles exceeds the optimal capacity and ends in a jamming concentration (k ). This indicates the formation of vehicle stagnation or queuing, commonly known as traffic congestion. During this phase, taking a private car is no longer a dominant strategy for commuters as they now bear social costs with other road users in the form of traffic congestion and associated time delays. Here, the outcome for an individual not only depends on his or her preferences concerning travel mode, but also on the preferences of others. In other words, an individual could enjoy the best strategy of taking private car only if others in the group prefer the optimal strategy of taking public buses and this interdependency leading to coordination problem in this phase.  The experimental economics approach because of its two main advantages over discrete choice models: i) observed behavioural patterns of commuters other than the hypothetical behaviour; and ii) the possibility of repeated interactions between commuters and institutions, which could help one to observe such behavioural patterns. Accordingly, a framed field mode choice experiment was designed and employed with real-world commuters. The main aim of the experiment was to explore the effect of demand-based traffic strategies to reduce the coordination problem among commuters in choosing between private and public modes of transport. Three demand-based traffic strategies involving three mechanisms-such as an incentive (bus subsidy), disincentive (parking cost) and persuasive (public coordination) measures-have been adopted.
The experiment was a coordination game with n (= 6) players who each make a choice to use the bus (x = 0) or car (x = 1) for commuting. The payoff for the individual player depends on their own decisions and those of the other players. The social optimum is to have one car and five participants on the bus.
Note that the individual in the car will have a higher payoff in the social optimum. Therefore, the social optimum is unstable. If players are selfish and rational and expect that others are too, Results were announced to all players after each round, though maintaining the anonymity of their choices. Subjects were not allowed to talk, and they were seated in a way that they could not directly see each other. A short general introduction was given by a facilitator. After questions from players were answered, subjects then received written instructions for the first exercise. After completion, instructions for the next exercise were distributed. Following the experiment, a brief survey was conducted which contained questions on the socio-economic background of participants, their everyday traffic behaviour and their attitudes regarding different policy measures and traffic-related problems.  The results show that the introduced treatments induce a modest increase in choosing the bus in the game. Increasing the parking costs or subsidizing the bus in the game has a positive effect. Table 1 shows   [8] Encyclopedia The results show that the introduced treatments induce a modest increase in choosing the bus in the game. Increasing the parking costs or subsidizing the bus in the game has a positive effect. The nonpecuniary treatment, the persuasive measure is a little less effective in reducing the number of cars, yet significantly increases participants' earnings because of enhanced coordination.

Results
The experiment highlights the interdependence effect within groups, i.e. participants made their own decisions based on the expected decisions of others. It is observed that participants chose the car less frequently when a monetary incentive for using public transport or avoiding the car is introduced.
Notably, it is also observed that providing information to facilitate coordination helped subjects to improve their earnings. Thus the experiment disentangles complex causal relationships by testing traffic policies in the field under controlled conditions. In this way, experimental research in transportation economics could generate further interesting insights for demand-side measure policy debates and enrich the current discourses therein.

Endnote
Traffic flow, also known as traffic volume, is defined as the number of vehicles expressed in terms of passenger car units passing a specified point during a stated period of time.
Density, also known as concentration, is defined as the number of passenger car units present in a stated length of road at any given time.
This indicates that the traffic flow (q) is stable, as it has reached the optimal capacity of the road (k ). Technically, roads should be built at this optimal road capacity (k ).