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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

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I What is distance decay?

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

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

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

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Distance decay: the formula p = f(d)

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

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

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Tested functional forms Source: Martínez and Viegas (2013)

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DD functional forms

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Exponential vs cubic vs linear

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

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Linear model to the data

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Cubic polynomial models

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Log-square-root model

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

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

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Distance and energy use

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Distance and mode dependence (Sheffield)

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

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

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III The uses of distance decay

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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)

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

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DD to characterise travel systems

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Modelling travel Source: Lovelace et al. (2014)

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IV Wider context of distance decay

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Resulting report: national benefits

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

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

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

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DD in the NPCT

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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

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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