An Overview of Studies and Applications on Traffic Performance Index

In order to quantitatively analyze the characteristics of traffic congestions,different models of traffic per-formance index (TPI)have been developed and applied in several cities.This study first analyzes the mechanisms,charac-teristics,and basic parameters in current models of TPI.Then,divide these models into two categories:macroscopic static models based on statistics,and dynamic models based on real-time data.The dynamic models are further divided in-to two sub-categories:models based on mileage fraction of severe congestions,and models based on travel-time ratio.By estimating TPI,this study comparatively analyzes the consistency,differences,and the sensitivity of these two sub-cate-gories of dynamic models based on the floating car data collected in the City of Beijing.