Drive time software is very popular in real estate research. Click on the map and it uses computerized roads to estimate how long it will take to drive from where you clicked. Typically, the software will estimate travel time bands, so, you'll end up with an area on the map that represents travel time of at most 10 minutes, 20 minutes...
Its interesting to note that these estimates are taken as exact. Of course, they are not. When you click on the map, you are not asked for what day, or what time of day you are estimating travel. We all know about rush hour and we all know that Saturday is different than Tuesday. In some areas, summer is different than winter.
It would be a lot to ask the drive time software to estimate this. They'd have to have a tremendous amount of data with each road segment to make it happen. The cost alone would surpass the benefit to knowing this precisely.
But one could estimate it. When making a drive time analysis, increase and decrease the estimate by 10, 20, and 30%. Have 10, 9, 8 minute drive time bands. Then conduct sensitivity analysis - what different decision(s) would you make if the travel time is really 8 or 11 minutes?
If the decision is the same, then it is probably straight forward. If the decision is different, then the right decision is sensitive to the underlying assumptions. More than likely, drive time is not the only data point that is confusing the decision, but not completely trusting a drive time estimate may help point out uncertainty.
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