Mapnificent is a tool that visualizes the places you can reach on public transportation given a certain amount of time. Custom settings let you note how long it takes you to get to transit stations, with an experimental option to calculate traffic by adjusting for time of day (though it doesn’t seem to account for L.A.’s gridlock).
There are maps for Los Angeles, San Diego, Sacramento and the Bay Area. (via highcountrynews)
Map: Shows areas available by public transit within 15 minutes from the Los Angeles Times. Credit: Mapnificent