Time-Based Map Regions

Problem: Google maps is presented spatially, like traditional maps. But Google maps has some additional intelligence that I would like to be able to tap into - it knows the speed limits and driving conditions of roads.

Solution: It would be nice to be able to enter a starting point and a period of time, and have Google maps show the entire region that can be reached in that time. There might be two ways to do this. A crazy way would be to visually collapse certain segments of the graph. The map would not be to scale, but a circle would then encompass all of the routes that could be reached. Probably the easier solution is to just draw a colored line on each road of the map, with the color extending to the limit that can be reached. For example, if the starting spot is Philadelphia, PA and the time is 2 hours, there would be red lines going up 95 towards New York, down 95 towards DC, part of the way across the PA turnpike towards Pittsburgh, etc. This would be a great feature for scheuduling a weekend getaway, etc.