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?