1. Risk Attitude Reversals in Drivers’ Route Choice When Range of Travel Time Information Is Provided Megan Englert Tim Leser

2. Purpose The goal of this work is to investigate the influence of range of travel time on drivers’ risk attitude, and whether a model can account for this influence.

3. Background Support Katsikopoulos et al. (2000) found that risk attitude and route choices were heavily influenced by whether or not the route choice belonged to the domain of gains or losses.

4. Theoretical Basis The basis for analyzing this model is whether or not it can predict for which route choice scenarios drivers are risk averse or risk seeking. This idea comes from the language of psychology of choice.

5. Practical Contributions The efficiency of the transportation networks can be improved. Support drivers’ decisions.

6. Theoretical Contributions Empirically demonstrates the influence of the range of travel times on drivers’ risk attitude. A simple model that predicts drivers’ risk attitudes, given route choices

7. Methods The study was performed on two routes (I-93 & Route 28). Both of these routes lead to downtown Boston. Subjects (15 men, 15 women) were recruited from the University of Massachusetts and the local area.

8. Methods A driving simulator was used to perform the experiment. Subjects were instructed to drive in the right lane, and follow a lead vehicle. The lead vehicle was used to control the subjects speed.

9. Methods Subjects were given a reference route (I-93) with range of travel time ‘c’, and an alternative route (Route 28) with a range of travel times ‘r’. 6 virtual traffic databases each containing 1 of 6 VMS (Variable Message Sign) were used to create 36 driving scenarios.

10. Methods Information of the ranges of travel times for each route was displayed in on the VMS on the right side of the road Subjects spoke aloud their route choice, and the experimenter recorded it

11. Analyses(figure 2)

12. Analysis(figure 3)

13. Analyses(figure 4)

14. Analyses The data were analyzed using a 2x3x6 ANOVA, with repeated measures.

15. Results Drivers diverted significantly less often as the alternative expectation increased. The effect of alternative range was also significant. This depended on the level of alternative expectation.

16. Results The results imply that drivers are risk seeking when (gains) and risk averse (losses) when the reference range of travel times is larger than the alternative range.

17. Future Work Perform these tests in other cities, without letting participants know what the study is. Possible by using GPS devices. This work was performed when the subjects had two choices, try to model n route choices.

18. Discussion Questions Thoughts