Under earthquake impacts, the failure of transportation infrastructure not only hinders normal everyday activities, but also impairs the post-disaster response and recovery, resulting substantial socio-economic losses. This paper describes recent developments of the network loss analysis (NLA) module for transportation system functionality assessment at the Mid-America Earthquake (MAE) Center. Traffic assignment models are used to evaluate the travel delays on the transportation network. The network loss analysis module is demonstrated through a case study of the real-world road network in the seismically vulnerable St. Louis metropolitan area. The MAEViz NLA module is useful to evaluate system performance of transportation systems for emergency management. The results of traffic flow and travel delays provide useful information for emergency managers and relevant government agencies to make emergency response plans for ingress and egress of impacted area (e.g. disaster relief dispatch and evacuation), and to indentify emergency routes and evaluate their performance under extreme events.