Citation

Li H, Graham DJ. Accid. Anal. Prev. 2016; 93: 65-74.

Affiliation

Centre for Transport Studies, Imperial College London, UK.

Copyright

(Copyright © 2016, Elsevier Publishing)

DOI

10.1016/j.aap.2016.04.007

PMID

27173361

Abstract

This paper estimates the causal effect of 20mph zones on road casualties in London. Potential confounders in the key relationship of interest are included within outcome regression and propensity score models, and the models are then combined to form a doubly robust estimator. A total of 234 treated zones and 2844 potential control zones are included in the data sample. The propensity score model is used to select a viable control group which has common support in the covariate distributions. We compare the doubly robust estimates with those obtained using three other methods: inverse probability weighting, regression adjustment, and propensity score matching. The results indicate that 20mph zones have had a significant causal impact on road casualty reduction in both absolute and proportional terms.

Copyright © 2016 Elsevier Ltd. All rights reserved.

Language: en