Travel time maps
"Travel Time Maps" allow understanding how far in a region an individual can reach by a certain mode of transport, from a given starting location and starting time. Their more technical name is Isochronal maps (Iso= same, chronos=time, therefore lines reachable in the same time).
Travel Time Maps are proposed as useful by public transport researchers (such as on Jarett Walker's blog Human Transit) in helping people think about their transport system in terms of a geography of mobility and accessibility.
- http://www.mapnificent.net - Free simple travel time maps for cities with a public GTFS feed integrated into Google maps
- http://www.mapumental.com - UK provider of Travel time maps service (originally free, now commercial)