Finding the Way Back: Variables in Asymmetric Route Choice

1. FINDING THE WAY BACK: variables in asymmetric route choice SSS6 Margarita Greene_Rodrigo Mora_Hernán Kirsten_Daniel Wurman

2. FINDING THE WAY BACK: variables in asymmetric route choice __________________the initial question ______________some relevant literature ________________________five cases ______________________final remarks

3. __________________the initial question ______________some relevant literature ________________________five cases ______________________final remarks

4. ROUTE CHOICE • recursive asymmetric trips as an opportunity to reveal relevant aspects in route choice • spatial variables_ • decision places during the trip_ • importance of visual fields_ • perception of distance_ _cost (time, money) _perception of risk _environmental factor _aesthetics

5. __________________the initial question ______________some relevant literature ________________________five cases ______________________final remarks

6. SPACE SYNTAX PERCEPTION OF DISTANCE: • _Canter and Kragg (1975) • …shorter routes are overestimated, while larger are underestimated • _Sadalla and Staplin (1980), Sadalla and Magel (1980) • …perception of distance is affected by turns and intersection • _Montello (1992) • …distance assessment can also be affected by memory loading • _Golledge (1995) asymmetric paths in a university campus • individuals paths vary in paper and real-world • individuals generally do not retrace routes, especially in orthogonal environments • they assign a “cost” to turns, preferring paths that demand fewer turns • individuals adapt their navigation decisions constantly

7. and within SPACE SYNTAX: • _Hillierand Iida (2005) • topological and angular properties of urban grids are better predictors of movement patterns than metric properties • _Conroy-Dalton (2003) • longest leg and angular deviation play a significant role in route choice • (the British Library theorem)

8. 66º 24º THE BRITISH LIBRARY THEOREM Conroy-Dalton (2003) • Spatial decision-making is a negotiation process • In metric and topological equal conditions, the longest leg route will be chosen providing that the path offers the minimum angle of deviation. • MINIMISING • ANGLES OF DEVIATION

9. __________________the initial question ______________some relevant literature ________________________five cases ______________________final remarks

10. FIVE CASES 30 students of the MSc Programme, Pontificia Universidad Católica de Chile were asked to recall a frequent asymmetric route from personal experience five cases were selected.

11. 1_Visual Assessment of Metric Distance Felipe Lanuza

12. Trip between office and University Campus. • Trip involves 8 turns and several street crossings. • It also involves crossing the Mapocho river. • Two Decision Points were identified: A and B. • Longest leg versus distance assessment are being negotiated at A and B. Due to street crossing a different balance results in the way to and fro. D-O O-D

13. B A

14. 2_First Leg Theorem and Preservation of Linearity Daniel Martínez

15. During path OD, the student somehow negotiates between continuing his path _maintaining his inertia_ or saving metric distance, though increasing the trip’s topological cost • During the return trip, the student faces the same negotiation. Both O-D trip and D-O trip involve two routes, each of them with one decision point: x and y respectively

16. 3_Assessing Angles in a Multiple Choice Trip 3_Enrique Gonzalez

17. As the student approximates the destination the angle of deviation changes reducing the “cost” of turning. • Again, as he reaches the origin the angle of deviation changes. • Both O-D and D-O trips involve three possible routes. • Two decision points at each of these trips: x,y and w,z

18. 4_Environmental Factors in Route Selection Jose Pablo Flores

19. The return trip is longer (98.4 vs 85.5 metres) yet simpler in topological terms. The student reports choosing the second trip because of its attractiveness. the OD route is clearly shorter , nevertheless the student chooses a longer route in the way back

20. 5_Avoid Backtracking 5_Hernan Kirsten

21. The OD trip starts with the longest leg and minimum angle deviation, yet is longer in metric terms. The choice of the return trip involves a small deviation _to the bakery_ and stop. This allows a reassessment of the trip, where the minimum angle deviation theorem again encourages the s2 route, specially considering that the backtracking is at the end of the journey and not visible form the Decision Point.

22. __________________the initial question ______________some relevant literature ________________________five cases ______________________final remarks

24. 1 2 3 FINAL REMARKS: • Backtracking: a natural instinct to avoid retracing steps. • Angular, topological and metric: negotiating process that individuals undergo negotiating distance against route complexity. • Compass orientation: a natural instinct towards the orientation of the destination. • Route inertia: routes have an inertia that has to be broken by an external stimulus • Unstable environments: urban space changes during the day and so offers a different choice during the day or season (for example car parks or traffic) • To and fro programs: the way towards a destination is less liable to be affected by secondary programmes, while the return trip looses urgency and is easily diverted • Visibility fields: length and area of visual fields affect the decision making process in route choice, although they can affect it in opposing ways (attracting or detracting alternatives) • Longest leg: the visible longest leg in direct route is more attractive in the route choice • Order and priority: perception of metric or topological costs vary according to the position in a path: a metric gain is perceived as more valuable at the beginning or a topological cost is perceived as less important at the end of the trip.