Comment by thrwyoilarticle

I use Google Maps via Android Auto. Sometimes I like to take a more scenic route, so I'll say:

'OK Google, avoid motorways'

And it will route me past anything officially called a motorway, sadly not including the A roads that are very similar.

Eventually I might decide I want to proceed more quickly, so I'll say:

'OK Google, use motorways'

At which point it will perform a Google search and read out the first result, a page from the government telling me how to use a motorway.