Introduction:
This web application is developed for the City of Houston Department of Public Works to enhance their capability to prioritize safety interventions on roads under their jurisdiction. This interface aims to consolidate disparate data sources, including both multi-model transportation features and socio-demographic characteristics, and introduce new risk analytics to aid in decision-making processes concerning road safety.

Instruction:
- Left function bar:
This bar contains all the layers categorized by road and demographic features. The drop down button for each map layer provideds multi-selection for filtering the data. For roads layer, its popup-window includes a trend graph of total number of crashes happened on this road. The crash data is aggregated by circles in proportional sizes, with a slider on the bottom left to query the time of the crashes. When clicking crashes, the popup-window will show with a yellow polygon, indicating the total number of crashes within this area. When zooming in the map, the aggregated circle will be split into individual points, indicating a single crash point. The popup window includes the basic information of the crashes and a Google Street View link.

- Right function bar: This bar contains functions related with visualizing and analyzing. Besides changing basemaps and showing the legends, Craph button shows the detailed number of injuries and fatalities in crashes. Users can also extract features through Select-by-Polygon with their own defined area-of-interest, which will query all the shown layers on the map with a spatial relationship and export these features into GeoJson format.