The concept of measuring traffic congestion has evolved over the past several decades. At the same time, congestion has "evolved" from a condition afflicting only central cities to a pervasive metropolitan problem. NCHRP Project 7-13, Quantifying Congestion, was assigned the task of developing methods to measure congestion on roadway systems. Its goals were to develop methods that are both reliable, user-friendly methods that can apply to a routes, corridors, subareas or entire urban region; can use simple and easy-to-use parameters; and can be forecast. The measures and methods described in this User's Guide (and the associated report Volume 1) are based on the needs for congestion and mobility information. These needs are best satisfied by travel time-related measures. The Guide also includes methods to adapt existing volume count and capacity estimation procedures to prepare congestion in appropriate formats. (A)
Abstract