Speaker
Description
As evidenced by the popularity of proposals to implement city-wide traffic speed limits (typically 30 km/h or 20 mph), lowering urban speed limits is increasingly acknowledged as a key measure to foster inclusive streets, improve liveability and reduce the environmental impacts of motorised traffic (Yannis and Michelaraki 2024). By diminishing the “radical monopoly” of motorised traffic on urban streets, lowering speed limits may contribute to increase equity between transport modes and social groups (Illich 1974). However, little research has sought to assess street speed limits through the lens of urban equity: existing research on urban speed limits tends to be rather technical and narrowly focused on their effects on traffic accidents and public health (Kravetz and Noland 2012; Cairns et al. 2015; Pilkington et al. 2018), rather than framed within broader conceptual debates related to urban equity and transport justice.
Responding to this research gap, the aim of the present paper is three-fold. Drawing upon existing reflections on the connection between transportation speed and socio-spatial justice (Illich 1974; Graham and Marvin 2001), at a theoretical level I seek to advance the idea that assessing the spatial distribution of street speed limits offers a novel and meaningful measure of urban equity. At a methodological level, I propose a method of extracting street speed limit information from OpenStreetMap data, and explore various indicators of speed limit distribution at a neighbourhood level. At an empirical level, finally, I assess the relationship between street speed limits and selected neighbourhood characteristics in Barcelona. Is the distribution of speed limits equitable between neighbourhoods, and to what extent do differences in speed limits between neighbourhoods reflect broader socio-spatial inequalities? In this respect, the present study seeks to contribute to the emerging body of literature assessing the spatial and social equity dimensions of traffic calming schemes (Aldred et al. 2021; Nello-Deakin 2024).
My analysis relies on publicly available street speed limit data from OpenStreetMap. To analyse and compare the distribution of street speeds limits between neighbourhoods, I extracted, cleaned and summarised speed limit information for all streets in Barcelona using the open software R, which I then used to calculate four proposed aggregate indicators of street speed limits at a neighbourhood level. To assess the extent to which the proposed speed limit indicators are related to key neighbourhood characteristics, I subsequently explored their relationship with selected neighbourhood level variables through bivariate correlation analysis.
My results show that average speed limits vary significantly between neighbourhoods, reflecting the existence of spatial inequities regarding the negative spatial externalities of automobility. Although my analysis shows that neighbourhoods with higher speed limits tend to have higher incomes and motorisation rates, it also draws attention to outlier neighbourhoods which combine high traffic speeds and low motorisation rates. From a distributive justice perspective, I argue that these outlier neighbourhoods can be thought of as being unfairly exposed to high traffic speeds which are mostly attributable to passing car traffic generated beyond the neighbourhood. Finally, I suggest that the proposed speed limit indicators could easily be replicated in other in other cities, enabling cross-city comparisons and facilitating the identification of leading cities in this domain, thereby providing a useful tool for research, advocacy and policy initiatives seeking to reduce urban traffic speed limits.
References
Aldred, Rachel, Ersilia Verlinghieri, Megan Sharkey, Irena Itova, and Anna Goodman. 2021. “Equity in New Active Travel Infrastructure: A Spatial Analysis of London’s New Low Traffic Neighbourhoods.” Journal of Transport Geography 96: 103194.
Cairns, Jo, Jon Warren, Kayleigh Garthwaite, Graeme Greig, and Clare Bambra. 2015. “Go Slow: An Umbrella Review of the Effects of 20 Mph Zones and Limits on Health and Health Inequalities.” Journal of Public Health 37 (3): 515–20. https://doi.org/10.1093/pubmed/fdu067.
Graham, Steve, and Simon Marvin. 2001. Splintering Urbanism: Networked Infrastructures, Technological Mobilities and the Urban Condition. London: Routledge.
Illich, Ivan. 1974. Energy and Equity. Ideas in Progress. New York: Harper & Row.
Kravetz, Daniel, and Robert B. Noland. 2012. “Spatial Analysis of Income Disparities in Pedestrian Safety in Northern New Jersey: Is There an Environmental Justice Issue?” Transportation Research Record 2320 (1): 10–17. https://doi.org/10.3141/2320-02.
Nello-Deakin, Samuel. 2024. “‘Winner’ Versus ‘Loser’ Streets? Pedestrianisation and Intra-Neighbourhood Equity.” Journal of Urban Mobility 5 (June): 100074.
Pilkington, Paul, Anna Bornioli, Issy Bray, and Emma Bird. 2018. “The Bristol Twenty Miles Per Hour Limit Evaluation (BRITE) Study.” University of West England.
Yannis, George, and Eva Michelaraki. 2024. “Review of City-Wide 30 Km/h Speed Limit Benefits in Europe.” Sustainability 16 (11): 4382.
| Keywords | street speed limits; urban equity; neighbourhood characteristics; OpenStreetMap |
|---|---|
| Best Congress Paper Award | Yes |
