We currently have a routing solution that uses NetEngine. This has the capability to allow the users to change speed limits on street segments and dynamically update the network file using the NetEngine API. We are rewriting the solution to use Network Analyst. I understand that it is not possible to directly edit the network dataset in the way the network file (.nws) could be edited with netengine. As far as I can tell, if we want to give the users the ability to change the speed limits on the streets, the only way to reflect it in the network dataset is to either rebuild the network or to tap into traffic data. My question is, is there a published format to generate traffic data feeds so we can control it or is it necessary to get the data from a third party vendor? Is there any other way in which changes can be made to a network dataset?