Principles of Highway Engineering and Traffic Analysis

"In many industrialized nations today, highways present engineers and governments with formidable challenges relating to safety, sustainability, environmental impacts, congestion mitigation, and deteriorating infrastructure. As a result, highways are often viewed from the perspective of the many challenges they present as opposed to the benefits they provide. Historically, highways have always played a key role in the development and sustainability of human civilization. Today, in the United States and throughout the world, highways continue to dominate the transportation system, by providing critical access for the acquisition of natural resources, industrial production, retail marketing, and population mobility. The influence of highway transportation on the economic, social, and political fabric of nations is far-reaching and, as a consequence, highways have been studied for decades as a cultural, political, and economic phenomenon. While industrial needs and economic forces have clearly played an important part in shaping highway networks, societies' fundamental desire for access to activities and affordable land has generated significant highway demand, which has helped define and shape highway networks. Without doubt, highways have had a dramatic impact on the environment in terms of the consumption of nonrenewable resources, air pollution, and the generation of greenhouse gases. In addition, vehicle crashes result in well over a million deaths worldwide every year and are the leading cause of death among people 15 to 29 years old [World Health Organization 2015]. As with other critical infrastructures (such as electrical power generation and distributions systems, water distribution systems, and storm-water and sewage systems), highway systems are costly to build, manage, and maintain, and inadequate management and maintenance can result in additional costs with regard to congestion, safety, and a variety of adverse economic impacts"--