Climate and Environmental Protection - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 236

15.7.1 Vehicle Technology

Road transportation emits approximately 3,500 9 10 6 t i.e., 7,717 9 10 9 lb CO 2
in the atmosphere yearly. This is approximately 0.2% of the absolute CO 2 content
of the atmosphere.
The pace of change in road transportation strongly depends on the price of oil.
Vehicles emit the highest amount of GHGs such carbon dioxide and other sub-
stances, which negatively influence the climate and the environment.
Besides regulations, the following measures can effectively reduce fuel con-
sumption and emissions:

• Widespread use of sensor, actuator and computer technology, data communi-
cation, stream lining, heat insulation, engine efficiency, light weight construc-
tion, etc.;
• Increasing driving efficiency with improved navigation;
• Financially right and socially well-balanced introduction of climate protection
measures, e.g., taxes;
• Reducing the transport demands between work and residences;
• Reorganization of districts for work, residence, and recreation in cities;
• Improvement of conditions in mass transportation; and
• Decreasing the costs of public transportation.

Changing the awareness of people depends more on motivation than on tech-
nology. Programs can teach drivers to save fuel and protect the climate.

15.7.2 Aviation Technology

Trends of gas and noise emissions in commercial aviation show that CO 2 emissions
will rise from the recent level of 733 9 10 6 t i.e., 1,615 9 10 9 lb to 1,480 9 10 6 t
i.e., 3,264 9 10 9 lb by 2025. NO and NO 2 mass is expected to grow from
2.5 9 10 6 t i.e., 5.513 9 10 9 lb in 2000 to 6.1 9 10 6 t i.e., 13.40 9 10 9 lb by 2025.
Aviation intensively influences the climate because jet airplanes fly at high
altitudes near the tropopause and emit particles and gases, and leave contrails.
Both can increase cirrus cloud formation. Airplanes can also release chemicals that
interact with GHGs in the atmosphere. Nitrogen compounds are particularly
dangerous, because they destroy ozone molecules at high altitudes.
Emissions from passenger aircraft vary per passenger kilometer, according to
the size of the aircraft, the number of passengers on-board, and the cruising
altitude. The rule of thumb shows that the average level of emissions depends on
the distance of the flight:

• Short-haul airplanes on flights under 463 km (288 mi) or under 3 h emit
approximately 259 g km -1 of CO 2 (9.1 oz km -1 or 14.71 oz mi -1 );