Adjustments to drive time estimates

Discussion created by mguaglia on Feb 25, 2011
Latest reply on Mar 3, 2011 by mguaglia
We estimate the drive time between each of 8.5 million U.S. residential locations and the nearest of any of 900+ service locations. From these estimates we calculate access statistics by planning region. We are using Network Analyst 9.3 and StreetMap Premium (not Advanced). We will soon be upgrading to 10.

Our regional planners and other colleagues are concerned that the drive time estimates are often too low, i.e. not real world. They want us to make adjustments for "in traffic" conditions, thus we are exploring StreetMap Premium Advanced (and weighing its advanced pricing.)

However, we are also being pressured to develop other kinds of adjustments, such as seasonal adjustments for icy roads, or "population density", or "geographic isolation". We don't entirely understand what such adjustments would entail and we are resisting them. Our current position is that we are in no position to improve on the drive times estimated by Network Analyst and StreetMap Premium. We cannot ground truth the entire U.S.

That said, we would like to be as informed as possible on the matter. Does anyone know of literature or white papers where others have evaluated adjustments to drive time other than rush hour adjustments? Thanks.