www.geog.leeds.ac.uk/people/r.lovelace http://robinlovelace.net

1. Estimating distance decay:
for the National Propensity to Cycle Tool (NPCT)
Robin Lovelace, University of Leeds.
Talk at the Institute for Transport Studies (ITS)
Slides: speakerdeck.com/robinlovelace

2. I What is distance decay?

3. Discovering distance decay
Source: Lovelace (2014): my thesis

4. Distance of trip != distance/yr
Source: Lovelace (2014): my thesis

5. Distance decay in active travel
Data: derived from Iacono et el. (2010)

6. Distance decay: the formula
p = f(d)

7. Euclidean or route distance?
Source: Lovelace (2014): my thesis

8. Distance decay in the literature
Source: Lovelace et al., forthecoming.

9. Tested functional forms
Source: Martínez and Viegas (2013)

10. DD functional forms

11. Exponential vs cubic vs linear

12. Some real data
Source: Lovelace et al.
(forthcoming)

13. Linear model to the data

14. Cubic polynomial models

15. Log-square-root model

16. II Why distance decay?
Source: NPCT model
Output (Leeds)

17. Distance decay in everyday life
Source: Lovelace (2014): my thesis

18. Distance and energy use

19. Distance and mode dependence (Sheffield)

20. Distance and mode dependence (England)
Source: Lovelace (2014): my thesis

21. Energy and travel mode
Source: Lovelace (2014): my thesis

22. III The uses of distance decay

23. Uses of dd: a few ideas
● If we're to transition away from fossil fuels, we
must use modes that are less energy intensive
● Distance decay for sustainable travel modes
can tell us what future travel patterns must look
like
● Characterising travel systems
● Especially relevant for active travel
● The National Propensity to Cycle Tool (NPCT)

24. 'Spatial
interaction
models'
Source: Lovelace et al.
(forthecoming),
Geographical Analysis

25. DD to characterise travel systems

26. Modelling travel
Source: Lovelace et al.
(2014)

27. IV Wider context of distance decay

28. Resulting report: national benefits

29. Benefits of cycling nationwide
See https://tinyurl.com/conversation-cycling

30. Webtag estimates of benefit:cost
See https://tinyurl.com/conversation-cycling
https://www.gov.uk/government/publications/webtag-
tag-overview

31. An open source policy planning tool
(+ live demo!)

32. DD in the NPCT

33. Further work on distance decay
● The distance-decay of road traffic incidents?
● Its use to estimate non-work travel?
● Verification of dd parameters using Big Data

34. Key references
● Iacono, M., Krizek, K. J., & El-Geneidy, A. (2010). Measuring non-motorized
accessibility: issues, alternatives, and execution. Journal of Transport Geography,
18(1), 133–140. doi:10.1016/j.jtrangeo.2009.02.002
● Lovelace, R., Clarke, M., Cross, P., & Birkin, M. (n.d.). Verification of big data for
estimating retail flows: a comparison of three sources against model results.
Geographical Analysis.
● Lovelace, R., Malleson, N., Harland, K., & Birkin, M. (2014). Geotagged tweets to
inform a spatial interaction model: a case study of museums. Arxiv Working Paper.
● Lovelace, R. (2014). The energy costs of commuting: a spatial microsimulation
approach. University of Sheffield. Retrieved from
http://etheses.whiterose.ac.uk/5027/
● Martínez, L. M., & Viegas, J. M. (2013). A new approach to modelling distance-
decay functions for accessibility assessment in transport studies. Journal of
Transport Geography, 26, 87–96. doi:10.1016/j.jtrangeo.2012.08.018