An interesting tool for viewing transit travel times in many cities is available at Mapnificent.  Using schedule data published by many transit agencies, you can view the area to which someone can travel within a given time, on a specific type of day and day of the week.  Playing around with the parameters gives different views depending on available transit services, walking time to stations/stops, and of course, your location.

A few things I have noticed using this site for Toronto:

• The route/schedule information appears to be a bit out of date because late night Sundays still show transit access via routes that no longer operate.
• There doesn’t appear to be a provision for the effect of waiting time at stops.  If a bus runs half-hourly, and you want the “15 minute” travel boundary, then most of your average trip will involve wait time.  According to the comment thread on a post linked below, no wait penalty is assigned for the route at the start of a trip, only for transfers along the way.

All the same, it’s an interesting way of looking at transit travel and comparing the reach transit provides in different parts of Toronto and the GTA.  Something like this would be ideal for visualizing proposed transit networks if one replaced the transit system as it is today with “tomorrow’s” version.

Have fun playing with the site.  Note that this is a beta version, and some things may not work quite as advertised.  Also, note that this is a very cpu-intensive application, and changing the display parameters may take a while for the update to complete.

See also these articles on Jarrett Walker’s Human Transit blog:

mapnificent breaking through?

beyond transit scores