1.6 million UK traffic accidents

### Context
The UK government amassed traffic data from 2000 and 2016, recording over 1.6 million accidents in the process and making this one of the most comprehensive traffic data sets out there. It's a huge picture of a country undergoing change.

Note that all the contained accident data comes from police reports, so this data does not include minor incidents.

### Content
`ukTrafficAADF.csv` tracks how much traffic there was on all major roads in the given time period (2000 through 2016). AADT, the core statistic included in this file, stands for "Average Annual Daily Flow", and is a measure of how activity a road segment based on how many vehicle trips traverse it. The [AADT page on Wikipedia](https://en.wikipedia.org/wiki/Annual_average_daily_traffic) is a good reference on the subject.

Accidents data is split across three CSV files: `accidents_2005_to_2007.csv`, `accidents_2009_to_2011.csv`, and `accidents_2012_to_2014.csv`. These three files together constitute 1.6 million traffic accidents. The total time period is 2005 through 2014, but 2008 is missing.

A data dictionary for the raw dataset at large is available from the UK Department of Transport website [here](http://data.dft.gov.uk/gb-traffic-matrix/all-traffic-data-metadata.pdf). For descriptions of individual columns, see the [column metadata](https://www.kaggle.com/daveianhickey/2000-16-traffic-flow-england-scotland-wales/data).

### Acknowledgements

The license for this dataset is the Open Givernment Licence used by all data on data.gov.uk ([here](http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/)). The raw datasets are available from the UK Department of Transport website [here](https://www.dft.gov.uk/traffic-counts/download.php).

### Inspiration

* How has changing traffic flow impacted accidents?
* Can we predict accident rates over time? What might improve accident rates?
* Plot interactive maps of changing trends, e.g. How has London has changed for cyclists? Busiest roads in the nation?
* Which areas never change and why? Identify infrastructure needs, failings and successes.
* How have Rural and Urban areas differed (see `RoadCategory`)? How about the differences between England, Scotland, and Wales?
* The UK government also like to look at miles driven. You can do this by multiplying the AADF by the corresponding length of road (link length) and by the number of days in the years. What does this tell you about UK roads?

### 背景
英国政府在2000年至2016年期间累积了交通数据，在此过程中记录了超过160万起事故，使之成为现有交通数据集中最为详尽的一个。这描绘了一个正在变革的国家全貌。

请注意，所有包含的事故数据均来源于警方报告，因此该数据集不包括轻微事故。

### 内容
`ukTrafficAADF.csv` 记录了给定时间段（2000年至2016年）内所有主要道路上的交通流量。该文件中包含的核心统计数据 AADT（年平均日流量），是根据通过该路段的车辆行程次数来衡量道路活动量的一个指标。[AADT 在维基百科上的页面](https://en.wikipedia.org/wiki/Annual_average_daily_traffic)是了解此主题的绝佳参考资料。

事故数据分为三个 CSV 文件：`accidents_2005_to_2007.csv`、`accidents_2009_to_2011.csv` 和 `accidents_2012_to_2014.csv`。这三个文件共同构成了160万起交通事故。总时间段为2005年至2014年，但2008年数据缺失。

关于整个原始数据集的数据字典，可从英国交通部网站[此处](http://data.dft.gov.uk/gb-traffic-matrix/all-traffic-data-metadata.pdf)获取。对于各个列的描述，请参阅[列元数据](https://www.kaggle.com/daveianhickey/2000-16-traffic-flow-england-scotland-wales/data)。

### 致谢
本数据集的许可协议为 data.gov.uk 上所有数据通用的开放政府许可([此处](http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/))。原始数据集可从英国交通部网站[此处](https://www.dft.gov.uk/traffic-counts/download.php)获取。

### 灵感
* 交通流量的变化如何影响事故率？
* 我们能否预测未来的事故率？哪些因素可能提高事故率？
* 绘制交互式地图以展示变化趋势，例如：伦敦对于骑行者的变化？全国最繁忙的道路？
* 哪些地区从未发生变化以及原因是什么？识别基础设施需求、缺陷和成功案例。
* 农村和城市地区有何不同（参见 `RoadCategory`）？英格兰、苏格兰和威尔士之间的差异如何？
* 英国政府还喜欢观察行驶里程。您可以通过将 AADF 乘以相应道路的长度（链长度）和年份中的天数来计算行驶里程。这能告诉我们关于英国道路的哪些信息？