One of the main concepts with the design of the user interface is that it must be kept simple and intuitive so that users without modelling knowledge can use the tool quickly and with ease. Emphasis was placed on streamlining the design and flow of the UI making navigation and insight; a quick and simple process with no prior knowledge of the tool.

A lot of data is displayed in the interface and the way colour is used in the UI is important. So that users are not overwhelmed, neutral colours, such as white and greys are used for a lot of background information. Key information is pulled-out from the background with bold colours, allowing users to quickly assimilate the important information and see what they have edited. For example, users can select the Time of day and see the Travel time cost straight away as they are highlighted in bright purple. Key data is also shown in larger font than background information.

Making the UI accessible was another major consideration in the both design of the workflow and visual design. The UI designs draw on the government’s design principles for accessible websites. For example, symbols are used in the UI alongside important colour choices to ensure that users do not have to rely on colour alone to infer meaning from the UI, and there is an important contrast between key information and the background.

Using page formats that users will be familiar with and positioning common functions (such as login buttons) where users would expect them to be on most websites, helps users navigate the UI. As the user moves between pages, the formats and button hierarchies remain consistent, maintaining the ease of use. For example, having a call-to-action button in the same place on every page which takes users to the next step of the user journey helps users progress through the scenario setup more quickly. All these design choices ease cognitive strain and provide a more pleasant user experience.