Having paused for over two years, I’m back thinking about my old obsession: how to map travelling time. I have repeated the map I made for driving times in the UK, but this time starting at the Cherry Creek Shopping Centre in Denver, Colorado.
High resolution image available here. Suggestions for how to create isochrones gratefully received!
jamesgeo.com 
Hi James,
I like your isochrone map of Colorado and also of Britain, I just have one suggestion, to use a different color set. The rainbow colors above are some what hard to concentrate at http://colorbrewer2.org/
A valid point – I shall use better colours for the next iteration!
You’ll probably enjoy Mapnificent too; in particular, http://www.mapnificent.net/denver/ .
You’re right – I did!