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A decibel is a unit of measure of the intensity of acoustic pressure. 0 dB is barely perceivable by human beings, while 120 dB is considered the threshold of pain and hearing damage. Decibels are measured on a logarithmic scale, which means that an increase of 10 dB corresponds to

Transportation systems, by their inherent characteristics, have an impact on the environment: Network. The structure of transportation networks influences the spatial distribution of emissions. Centralized networks experience a concentration of traffic and emissions at specific locations (hubs), but are using less energy since the average distance is shorter. Dispersed networks

Source: adapted from K. Button, Center for Transportation Policy, Operations and Logistics, George Mason University, Lecture Notes. The spatial and temporal dimensions are important to consider when assessing the impacts of environmental externalities, such as pollutants. The more extensive the spatial and the temporal dimensions, the more difficult it is

Transportation activities involve separate modes supporting the mobility of passengers and freight (within or between modes). Each has an environmental impact: Infrastructure. Transport infrastructure construction and maintenance require resources (materials), energy, and land. Vehicle manufacture. Involves the resources and energy consumed in the manufacturing process. This also includes the delivery

Source: Bureau of Transportation Statistics, National Transportation Statistics, Table 3-17. Assumes 15,000 miles of driving per year. Figures are in 2020 dollars. The costs of using the automobile can be divided into three categories: Internal variable costs. These costs vary according to the amount of travel. They include gasoline, maintenance,

Source: adapted from US Environmental Protection Agency (2000) The Lean and Green Supply Chain: A Practical Guide for Materials Managers and Supply Chain Managers to Reduce Costs and Improve Environmental Performance, Environmental Accounting Project, EPA 742-R-00-001. To produce and make goods available on the market, a hierarchy of environmental costs

Source: adapted and expanded from CEMT, 1990. There are a number of relationships between the atmosphere, the hydrosphere, the lithosphere, and the ecosphere, and some noted impacts.

The environmental system may be understood in an ecological sense as the set of interactions between the elements of the biosphere, which includes the atmosphere, the hydrosphere, the lithosphere, and the ecosphere: The atmosphere is a mixture of nitrogen (78%), oxygen (21%), and traces (remaining 1%) of carbon dioxide, argon, water

Mobility conveys various benefits, including access to employment, goods, and social activities. The paradoxical relation between mobility and its costs is based on the premise that the benefits are derived by the users of transport systems (e.g. drivers) and that the costs are in part assumed by society and the