Last week you used ArcView and Excel to generate trips for the Ames network. What you did, however, was just looking at internal trips, or, trips that were produced and attracted within the network. Today, you will try to get a handle on how to deal with IE, EI and EE trips. When we set up our networks, you were asked to put important roads into your model. The nodes at the edge of the network are known as external stations and the links that connect them to internal network nodes are called external connectors.
External stations are similar to TAZs at the boundaries of the network.
Any roads that cross the cordon are external connectors and they need to terminate at an external station. Typically, the AADT is collected for each roadway to be included in the model. Each technique uses slightly different assumptions which you should evaluate before using. Perform this analysis for the eight external stations in Ames listed above. The second technique is simpler.