An experimental study of the Online Information Paradox: Does en-route information improve road network performance?

This study investigates the empirical presence of a theoretical transportation paradox, defined as the “Online Information Paradox” (OIP). The paradox suggests that, for certain road networks, the provision of online information deteriorate travel conditions for all users of that network relative to the situation where no online information is provided to users. The analytical presence of the paradox was derived for a specific network structure by using two equilibrium models, the first being the Expected User Equilibrium (EUE) solution (no information scenario) and the other being the User Equilibrium with Recourse (UER) solution (with information scenario). An incentivised computerised route choice game was designed using the concepts of experimental economics and administered in a controlled laboratory environment to investigate the physical presence of the paradox. Aggregate statistics of path flows and Total System Travel Costs (TSTC) were used to compare the experimental results with the theoretical findings. A total of 12 groups of 12 participants completed the experiment and the OIP and the occurrence of the OIP being significant was observed in 11 of the 12 cases. Though information increased travel costs for users on average, it reduced the volatility of travel costs experienced in the no information scenario indicating that information can achieve a more reliable system. Further replications of similar experiments and more importantly field based identification of the phenomena will force transport professionals to be aware of the emergence of the paradox. In addition, studies such as this emphasise the need for the adoption of adaptive traffic assignment techniques to appropriately model the acquisition of information on a road network.


Individual Choice Task
The computer screen in front of you presents a table containing 10 choice scenarios. Each choice scenario involves you deciding between 2 options, option A and option B.
The first row indicates that option A gives you a 10% chance of getting $5 and 90% chance of getting $4, and that option B gives you a 10% chance of getting $9.75 and 90% chance of getting $0.25. Your task is to click on the option you prefer (A or B) for each choice scenario. When you have completed all 10 scenarios choosing between option A and option B, click on "confirm" to register these choices. Your choices can be changed as many times as you wish until you click on the confirmation button.
The payoff for this part will be determined in the following way. The central computer will pick randomly for each participant, one scenario, among the ten scenarios presented to you. Then, depending on the particular scenario selected by the computer, the computer will make an additional drawing lot in determining a number between 1 and 10. This number will finally determine your payoff for the individual choice task.
Let's take an example. Assume that the computer picked randomly for you, choice scenario 3, where you chose option A. In this situation, option A gives you a 30% chance to get $5 and a 70% chance to get $4. If the computer randomly chooses a number between 1 and 10 by the computer which is either 1, 2 or 3, you will get $5 and if the number is 4, 5, 6, 7, 8, 9 or 10, you will get $4. If for choice scenario 3, you chose option B, you will gain $9.75 if the number is between 1 and 3 and $0.25 if the number is between 4 and 10.
The payoff for the individual choice task will be part of your final payoff, as explained before.
Please raise your hand if you are unclear with the instructions.

Please wait for further instructions.
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Game 1
Consider the traffic network presented in the figure below. Each driver is required to choose a route in order to travel from the starting point, denoted by A, to the final destination, denoted by D. There are three alternative routes and they are represented in the diagram as [A-B-D], [A-C-D] and [A-C-B-D]. The number of drivers selecting each road, in other words the volume of traffic on each road, is denoted by " " where refers to the relevant road. Travel from an origin to a destination bares a cost for each individual, the cost of time, fuel and any tolls incurred along the route. In addition there are uncertainties when travelling, incidents may arise, weather may create difficulties in driving or there may be an excessive number of vehicles on the network due to peak travel conditions. These types of factors affect the state of the network and the travel costs for each road on the network.
In this particular network, the cost of traveling on each of the road segments (provided in "units") is written near the labels of the road segments. The costs of roads A-B and C-D are fixed at $10, while the cost of A-C and B-D are dependent on number of motorists travelling on the road segments, denoted by − and − respectively. The network describes a scenario where there is a 20% chance of an incident occurring on road segment C-B which increases the fixed cost of road segment C-B from 1 unit to 20 units as the disruption increases travel time and fuel costs.
Your activity will be to select the route which you think would be the best to travel from node A to node D. You will NOT know any information about the presence of an incident on C-B prior to making your route selection.

Procedure for Game 1
At the beginning of each round, the computer terminal in front of you will show you the network diagram, presented in Figure  Once you click on a specific road segment of a route, that segment will be highlighted in a red colour. If you make an error whilst clicking on a road segment you should either click an alternative road segment or click "Cancel" to restart the selection process. After you have connected origin A and destination D with a feasible route that you would choose to travel on, you will be asked to "Confirm" your route by pressing the "Confirm" pop-up button if you are satisfied with your selection. 2. After confirming your route choice, you will be presented with a message to wait until all other participants have made their decisions. 3. Upon the completion of the task by all participants the computer will present you with the following information; a. The traffic conditions of Link C- . You will complete this activity for 20 rounds. At the completion of 20 rounds, the computer will inform you that Game 1 has been completed. A further message will be provided to "Please wait until the experiment continues" All the decisions will only be made by clicking the "mouse" of the computer; there is no need to type anything whilst participating in the game.
You will receive 45 units of income for each round. The payoff for each round will be determined by the following equation:

Payoff = (45 -Total Cost of travel) units
All 20 rounds will have the same structure.
At the end of both games (Game 1 and Game 2) you will receive payment for a randomly selected round from each of the games. You will receive $0.25 for every unit of payoff earnt in the randomly selected rounds of each of the games.

Let's consider that in the first round you are the only one to choose route [A-C-B-D], 6 participants choose [A-B-D] and 5 participants choose [A-C-D]
 If road C-B does NOT experience an incident, the cost of using road A-C is 6 units (5 people using A-C-D and you are using A-C-B-D), the cost of using road C-B is 1 unit and the cost of using road B-D is 7 units (6 people using A-B-D and you are using A-C-B-D). Therefore your total cost will be (6+1+7) = 14 units for that round. (Figure 2)  If road C-B experiences an incident, the cost of using road A-C is 6 units, the cost of using road C-B is 20 units (fixed cost) and the cost of using road B-D is 7 units (6 people using A-B-D and you are using A-C-B-D). Therefore your total cost will be (6+20+7) = 33 units for that round. (Figure 3)  If road C-B does NOT experience an incident, the cost of using road A-C is 8 units (3 people using A-C-B-D and 5 people using A-C-D), the cost of using road C-B is 1 unit and the cost of using road B-D is 7 units (3 people using A-C-B-D and 4 people using A-B-D). Therefore your total cost will be (8+1+7) = 16 units for that round. (Figure 4)  If road C-B experiences an incident, the cost of using road A-C is 8 units, the cost of using road C-B is 20 (fixed cost) and the cost of using road B-D is 7 units. Therefore your total cost will be (8 + 20 + 7) = 35 units for that round. (Figure 5) Please raise your hand to indicate that you have completed reading these instructions and understood the rules of the game.
Game 1 will begin shortly.
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Game 2
Similar to Game 1, consider the traffic network presented in the figure below. Each driver is required to choose a route in order to travel from the starting point, denoted by A, to the final destination, denoted by D. Like before, there are three alternative routes and they are represented in the diagram as:

[A-B-D], [A-C-D] and [A-C-B-D].
However the difference with Game 2 is that at node C you will be provided information about the state of Road C-B, analogous to a Variable Message Sign indicating the traffic conditions of the route ahead. The travel costs, the likelihood of an incident being present on C-B (An incident may eventuate 20% of the time) are identical to what was observed in Game 1. The only difference is that the presence of an incident will be revealed to you at node C if you initially choose road A-C. As with Game 1, please note that the cost charged on roads A-C and B-D of the network depend on the number of motorists choosing them.
Your activity will be to select the route which you think would be the best to travel from node A to node D. If you travel to node C you will be provided information about the presence of an incident on C-B prior to making your route selection.
Please raise your hand to indicate that you have completed reading these instructions and understood the rules of the game.
Game 2 will begin shortly.
Do NOT turn over the page until instructed to do so.