Emission from motor vehicles is a major source of air pollution. Accurate emission estimation is imminent to effectively control air pollution. Modal emission models are the thrust of recent researches and it overcomes some of the shortcomings in the existing emission rate models. The primary input to modal emission models is the fraction of time spent in different driving patterns. However, the static travel demand model hampers accuracy of predicting driving patterns. This book illustrates an approach to predict driving patterns more accurately by considering a set of emission specific characteristics (ESC) for each network link. ESC considered in this research includes geometric design elements, traffic characteristics, roadside environmental characteristics, and driver behavior. Geometric design elements of roads exert greater influence on driving patterns than the traffic, the roadway environmental and the driver characteristics and in turn on the quantum of emissions. This book provides a valid methodology for emission estimation based on available data sources with marginal increase in cost and will be highly useful to traffic agencies and practitioners."