Ex. 5. Read the text attentively and learn how scientists try to solve ecological problems produced by transport.



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Ex. 5. Read the text attentively and learn how scientists try to solve ecological problems produced by transport.



Transport is a major use of energy, and transport burns most of the world's petroleum. Transportation accounts for 2/3 of all U.S. petroleum consumption.

The transportation sector generates 82 percent of carbon monoxide and 56 percent of NOx emissions and over one-quarter of total US greenhouse gas emissions. Hydrocarbon fuels also produce carbon dioxide, a greenhouse gas widely thought to be the chief cause of global climate change, and petroleum-powered engines, especially inefficient ones, create air pollution including nitrous oxides and particulates.

Although vehicles in developed countries have been getting cleaner because of environmental impacts of transport systems include traffic congestion and automobile-oriented urban sprawl, which can consume natural habitat and agricultural lands. Toxic runoff from roads and parking lots can also pollute water supplies and aquatic ecosystems.

Alternative propulsion can reduce pollution. Low pollution fuels may have reduced carbon content, and thereby contribute less in the way of carbon dioxide emissions, and generally have reduced sulfur, since sulfur exhaust is a cause of acid rain. The most popular low-pollution fuels at this time are biofuels: gasoline-ethanol blends and biodiesel. Hydrogen is an even lower-pollution fuel that produces no carbon dioxide, but producing and storing it economically is currently not feasible. Plug-in hybrids are energy-efficient vehicles that are going to be in the mass-production.

Another strategy is to make vehicles more efficient, which reduces pollution and waste by reducing the energy use. Electric vehicles use efficient electric motors, but their range is limited by either the extent of the electric transmission system or by the storage capacity of batteries. Electrified public transport generally uses overhead wires or third rails to transmit electricity to vehicles, and is used for both rail and bus transport. Battery electric vehicles store their electric fuel onboard in a battery pack. Another method is to generate energy using fuel cells, which may eventually be two to five times as the internal combustion engines currently used in most vehicles. Another effective method is to streamline ground vehicles, which spend up to 75% of their energy on air-resistance, and to reduce their weight. Regenerative braking is possible in all electric vehicles and recaptures the energy normally lost to braking, and is becoming common in rail vehicles. In internal combustion automobiles and buses, regenerative braking is not possible, unless electric vehicle components are also a part of the powertrain; these are called hybrid electric vehicles.

To achieve real environmental objectives, attention should be focused on all motor vehicles, not just new vehicles. Features such as on board diagnostics systems can monitor engine output, while regular technical inspection reveals if vehicles are well-maintained and operating under optimal conditions.

It takes about ten years for the national vehicle fleet to be renewed. Providing incentives to replace old gas-guzzling vehicles with newer, fuel-efficient models, for instance payouts to scrap old vehicles, would speed up the process of fleet renewal and help reduce carbon gas emissions.

Oil companies are improving their petrol and diesel products, such as new environmental regulations and respond to new developments in engine technology.

Alternative fuels such as natural gas produce lower CO2 emissions.

On the other hand, so experts think that plant-based fuels may not provide the answer to CO2 emissions because of their negative overall energy and environmental performance from cultivation to final use.

Motor vehicles achieve optimal performance where traffic flow is most fluid. Ways of improving traffic fluidity, reducing congestion and hence lowering fuel consumption are:

· building new road infrastructure where necessary;

· improving current infrastructure;

· installing road signs providing both directions and information on the road network to allow tourists to choose the best route.

In the United States, for example, Intelligent Transport Systems (ITS) are being installed in 75 of the largest urban areas, an investment that should help reduce journey times by 15%.

Shifting travel from automobiles to well-utilized public transport can reduce energy consumption and traffic congestion.

Walking and bicycling instead of traveling by motorized means also reduces the consumption of fossil fuels. While the use these two modes generally declines as a given area becomes wealthier, there are some countries (including Denmark, Netherlands, Japan and parts of Germany, Finland and Belgium) where bicycling comprises a significant share of trips. Some cities with particularly high modal shares of cycling are Copenhagen (33%) and Groningen (50%). A number of other cities, including London, Paris, New York, Sydney, Bogota, Chicago and San Francisco are crating networks of bicycle lanes and bicycle paths, but the value of such devices for utility cycling is highly controversial.

 



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