I'd love to see this centered around my office which is not downtown. I'm southeast of town, and the areas I'd most like to live are north (near the Wisconsin River) or west (in the driftless area). Traffic in both directions can be congested.
Once upon a time ArcGIS had a demo page where you could output a .kml with the proper inputs. I used the shit out of it for our business plan. Thing of it is, that doesn't allow you to account for traffic; they likely did some serious Google Maps abuse on that one.
While nothing beats the ease of uploading a kml, there are now a bunch of APIs offering lots of awesome mapping services on demand. Esri offers it in-app but has a positively stupid method of payment, WSJ uses HERE's Routing API, and I'm currently experimenting with Mapzen Flex which has a ton of cool services for next to nothing. The thing about drive time data is that it is averaged from user GPS data, with usually only a binary 'traffic yes/no' as a variable to take into account - if you click on the HERE link you can see it doesn't give you many options. Might even be averaged over all days (including weekends) if HERE was particularly lazy. Edit: Oh, by the by, Mapzen offers an Explorer where you can generate some isochrones as well. rthomas6, how accurate is it if you zoom out?