Congestion can be characterized by many metrics and sourced from a variety of different data sources. For the purpose of analyzing congestion in the Tahoe region, TRPA collects data from Inrix and has calculated a congestion index for different multidirectional roadway segments. The congestion index measures the observed speed of a roadway segment in relation to the typical speed of that roadway segment. A roadway segment with a lower (negative) value indicates higher congestion. Lower negative values indicate that the observed speed on a roadway segment is much slower than the expected speed.