Effects of 20 mph interventions on a range of public health outcomes : a meta-narrative evidence synthesis
Abstract
Background Road traffic injuries are a leading cause of preventable death globally, but can be reduced by introducing speed lowering interventions such as 20 mph or 30 km/h speed ‘zones’ and ‘limits’. ‘Zones’ utilise physical traffic calming measures and ‘limits’ only utilise signage and lines. Transport is a social determinant of health and therefore such interventions may in/directly also impact on other health outcomes. Aim To investigate the effect of 20 mph speed ‘zones’ and ‘limits’ on a range of health outcomes, and to establish if there are differences in the effectiveness of 20 mph zones and 20 mph limits. Methods MEDLINE, EMBASE, Web of Science and Transport Research Information Service (TRIS) databases were searched [1983–January 2019) to identify relevant studies. Reference lists, relevant systematic reviews and the grey literature were also searched. Inclusion criteria: 20 mph ‘zone’ or ‘limit’ interventions: and public health outcomes (collisions, casualties, mode of transport, noise pollution, air quality, inequalities and liveability (e.g. physical activity and perceptions of safety)) and including a control/comparison group. Results Eleven studies were identified reporting nine 20 mph ‘zone’ and two 20 mph ‘limit’ interventions. 20 mph ‘zones’ were associated with a reduction in the number and severity of collisions and casualties; have less robust evidence of the effect on air pollution; and have the potential to indirectly impact physical activity and liveability through various mechanisms for change (although currently the evidence is lacking and requires further work). No significant associations were reported between 20 mph ‘limits’ and any public health outcome. Conclusion This review suggests 20 mph ‘zones’ are effective in reducing collisions and casualties. However, it provides insufficient evidence to draw conclusions on the effect of 20 mph ‘zones’ on pollution, inequalities or liveability. For 20 mph ‘limits’ more rigorous evaluations are required in order to draw robust conclusions.
Citation
Cleland , C , McComb , K , Kee , F , Jepson , R , Kelly , M P , Milton , K , Nightingale , G , Kelly , P , Baker , G , Craig , N , Williams , A J & Hunter , R 2019 , ' Effects of 20 mph interventions on a range of public health outcomes : a meta-narrative evidence synthesis ' , Journal of Transport and Health , vol. In Press , 100633 . https://doi.org/10.1016/j.jth.2019.100633
Publication
Journal of Transport and Health
Status
Peer reviewed
ISSN
2214-1405Type
Journal item
Rights
Copyright © 2019 Elsevier Ltd. All rights reserved. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1016/j.jth.2019.100633
Description
This study is part of a National Institute for Health Research (NIHR) funded project (PRP 17/149/19).Collections
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