I'm trying to find a mapping tool. Basically, I want to be able to chose several points on a map, chart a driving radius from each point based on time, then see where they all overlap.

Can anyone find a tool that does this?

So far I've found the following sites:

Drivingradius.com - Interesting, but does not calculate based on time at all, and doesn't seem to do multiple points. If you're looking to calculate distance, it looks great. It gives a perfect circle around a point to show a radius as the crow flies, and then also plots out how far from that point you can get by road. It's neat and works just how they made it, it's just not what I'm looking for.

How Far Can I Travel - Kind of close. The main problem is that it can't do multiple points. It will calculate how far from a point you can drive in a certain amount of time, but the problem is that it won't account for road speed. A 25mph neighborhood is given equal consideration to a four lane highway. The controls I'm given to adjust for this are very imprecise. Therefore I don't really trust the results.

That's all I've stumbled across so far. I feel like there should be a Google Earth plugin for this. Google knows how fast different roads are, don't they? I'm surprised that second site doesn't use that, unless the API doesn't give them access...