Describing traffic issues while driving needs to be done quickly, so the driver isn’t distracted too long. I feel at least 20 buttons should be shown on the screen right away to report conditions, instead of 5 that ‘open’ into related scenarios. So 1st column is the 5 most important police issues, the 2nd column is the 5 most important emergency vehicle issues, the 3rd column is the 5 most important crash or stopped vehicle issues, the 4th column is the 5 most important road surface condition issues, and the 5th column is the 5 most important ‘other’ issues.
With this sorted visual in place there is no going to subcategories, because all the most important things are displayed on the 1st screen.
The driver can quickly choose which ‘button’ to select from 1 screen instead of having to go to multiple screens, possibly taking their eyes off the road ahead for long enough to become a driving danger themselves because they are not paying attention to the road navigating extra screens and taking too much time.