  Measuring traffic performance is critical for public agencies who manage
traffic and individuals who plan trips, especially when special events happen.
The COVID-19 pandemic has significantly influenced almost every aspect of daily
life, including urban traffic patterns. Thus, it is important to measure the
impact of COVID-19 on transportation to further guide agencies and residents to
properly respond to changes in traffic patterns. However, most existing traffic
performance metrics incorporate only a single traffic parameter and measure
only the performance of individual corridors. To overcome these challenges, in
this study, a Traffic Performance Score (TPS) is proposed that incorporates
multiple parameters for measuring network-wide traffic performance. An
interactive web-based TPS platform that provides real-time and historical
spatial-temporal traffic performance analysis is developed by the STAR Lab at
the University of Washington. Based on data from this platform, this study
analyzes the impact of COVID-19 on different road segments and the traffic
network as a whole. Considering this pandemic has greatly reshaped social and
economic operations, this study also evaluates how COVID-19 is changing the
urban mobility from both travel demand and driving behavior perspectives.
