دانلود رایگان مقاله لاتین دوربین کنترل سرعت از سایت الزویر
عنوان فارسی مقاله:
اثرات رفتار ناهمگن دوربین های کنترل سرعت در امنیت جاده
عنوان انگلیسی مقاله:
Heterogeneous treatment effects of speed cameras on road safety
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
Speed limit enforcement cameras were first introduced in the UK in 1991 and were extended widely in the last decade. Numerous studies have been conducted to investigate the effect of safety cameras, and results show that the implementation of safety cameras has reduced vehicle speed and casualty numbers near camera sites (e.g. Mountain et al., 2005; Gains et al., 2004, 2005; Li et al., 2013). Despite the wealth of empirical evidence it remains unclear how such effects may vary across sites, referred to as heterogeneity of treatment effect (HTE). The hypothesis is that the variation in treatment effects is related to the differences in site characteristics, specifically the extent to which site characteristics meet treatment assignment criteria. The main objective of this study is to analyse how the site characteristics influence the effects of fixed speed cameras, and identify the locations which have benefited most from treatment. Although the importance of HTE has been widely recognized in causal analysis, most previous studies on speed cameras usually report an average treatment effect (ATE), which neglects the fact that the effects of speed cameras may differ systematically by site characteristics. This is due in part to the fact that causal approaches for exploring HTE, used routinely in other areas of science such as medicine and epidemiology, have not yet been adopted in road safety studies. Understanding HTE has important implications for policy making. Treatments or trials, such as speed cameras, are usually costly. For example, the annual cost of safety cameras is around £100 million for 2003/04 in the UK (Gains et al., 2005). It is desirable that the treatment is operated in a way that maximises effectiveness with limited resources. By revealing patterns of HTE, policy makers can assign treatments to units most likely to benefit from the treatment, so as to improve the cost-effectiveness of intervention. In this paper we tackle this issue by applying and developing causal approaches for estimating heterogeneous treatment effects of speed cameras on road casualties. The paper is organized as follows. The literature review is presented in Section 2. The method and data used in the analysis are described in Section 3 and Section 4. The results are presented and discussed in Section 5. The conclusions are given in the final section.
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