The Department of Transport produced this graph about HS2 in 2016 showing how journey times might change when HS2 is complete. Write down the name of this type of diagram.

The diagram is a type of bar chart. Specifically, because it places two bars side-by-side for each category (destination city) to allow for easy comparison between two different sets of data (current journey time vs. HS2 journey time), it is called a **comparative bar chart**. It is also known as a dual bar chart or multiple bar chart.