Great Arc has rolled out the upgraded version of the Iowa Department of Transportation Crash Analysis Tool (ICAT), a web-based mapping application that displays multiple years of traffic accident data for the entire State of Iowa. The application supports hundreds of users in local, regional, and state agencies, as well as the general public. Users may filter crashes by geographic location as well as by any of a multitude of attributes. Maps are rendered using the Esri JavaScript API for ArcGIS Server. We also developed REST services using ASP.NET Web API that communicate with the source Oracle database to provide data to the client application. Users can view project information, overview maps, and charts depicting selected crash data characteristics. The application also includes a custom report builder, powerful search and filtering capabilities, a full suite of navigation and drawing tools, heat mapping, “stacks” – which is a simulated 3-D view of multiple crashes at locations, and the ability to download and export maps and tabular data.