How are Time and Distance Buffers Calculated?
This is a raster map of a portion of a major city, but it could just as easily be your community. You can travel further on a limited access highway than a local road in the same amount of time due to the difference in speed limits. In it, you can see limited access highways, major roads with buildings on them, and local streets with homes. The speed limits on these streets vary depending upon their size and use. The routing server manages the speeds for each road type and uses those speeds to calculate the distance a driver could travel in a specific amount of time. For example a driver could get further in an hour on a highway, than on a local road, due to the average speed limits on those roads. If you think of these speed limits and distances in spatial terms, starting from a particular point, the region the web service could create along a highway would be longer and narrower than the region you would create using a more local road based on the same amount of time or distance requ
