Final Report March 2000
Figure 8.3.1. Spatial Structure of Taoyuan Airport City
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- 9.1 Policy Approach to Reduce Vehicle Emissions
- Improvement of Technical Efficiency of Vehicle Operation
- Development of lean burn engine
- Improvement of diesel engine
- 9.1.2 Policy to Improve Operational Efficiency of Transport System Efficient operation of transportation modes
- Transfer to public transportation modes
- Commuting Mode Average No. of Travelers Energy Consumption Rate (MJ/person/km)
- Energy Efficiency of Public Transportation Vehicles
TayuanFigure 8.3.1. Spatial Structure of Taoyuan Airport City 8.3.3 Conclusion While more and more construction projects of transportation system and land uses are developed using scarce natural resources, environmental conflicts of transportation and land uses have become worse. Facing a situation of increasing population and economic activities concentrated in urban areas, and changing value attitudes of people toward better environmental quality, it is a crucial task to manage environmental conflicts for sustainable development of natural and built environments. With imagination and professional knowledge, planning can be exercised to harmonize the transportation system and environmental system in a better way. Given the example of airport city presented in this paper, the economic benefits of airport can be maximized while its environmental conflicts are minimized by means of appropriate planning. However, it should be recognized that the example of Taoyuan airport city is by no means perfect, and other efforts are needed to carry out the plan. Ch 9. Air Quality Improvement, Accident Reduction and Energy Saving 9.1 Policy Approach to Reduce Vehicle Emissions Air pollution is the most typical type of environmental damages caused by vehicle transportation. Therefore, transportation policies should focus on the reduction of air pollutants from the vehicle emissions. The emission of the air pollutants are affected by various factors, and there are diverse policies to reduce air pollutants. These policies are categorized on the whole as follows:
In this chapter, the policy of lessening the use of energy in transportation and the emission of air pollutants will be dealt with briefly. Out of them, the most noteworthy is the method of restraining travel demand.
Improvement of engine Basically the gas mileage of gasoline engine is mainly affected by the mixed proportion of gas and air and firing timing. In recent years, the rapid advance in electronics have made it possible that the proportion and timing could go hand in hand with the externalities, and loading factors in optimal conditions. Additionally, the engine efficiency can be also enhanced with the development of multi-inhaling devices, number of valves, geometric structure, and other innovations. Development of lean burn engine Engine improvements above mentioned have contributed to the development of the lean burn engines. With the engine loading, the optimal gas and air could bring lots of benefits in cutting down pollutants emission as well as fuel cost. In general, it has been analyzed that the vehicles with lean burn engines can gain about 15% fuel cost saving in comparison to other regular vehicles. Improvement of diesel engine The perfect make-up between air and gas should be promoted in respect to the reduction in air pollutants as well as fuel cost, effects of which can be incremented by the complete combustion in diesel engine. To this end, the transformation of cylinder design, the device of its parts, such as piston , induction port and so on, are crucial to determine the emission level. Aerodynamics In case of a medium-sized European sedan, air resistance could be estimated as the 80 percent of total rolling resistance when it runs with a speed of 100km per hour. Therefore, lower air resistance coefficients could be a short cut to fuel cost saving. In general, it is estimated that about 10% decrease of air resistance coefficient is equivalent to about 5% fuel cost saving. Improvement of transmission It was reported that in case of automatic transmission, the vehicles with a newly-developed transmission of consecutive conversion could yield an additional 10% fuel cost saving in comparison to regular vehicles. It was also estimated that the possibility of saving fuel costs using the method of consecutive conversion can be culminated to the extent of about 20 percent. Reduction of car weight It is obvious that the method of decreasing vehicle weight results in fuel cost saving. This is more strikingly applied to the light vehicle rather than the heavy vehicle. In reality, this method is unlikely to be practiced owing to the fact that the vehicle weight is being augmented by the attachment of accessories. Despite of this trend, two measures are cautiously applied. One is that light metals might be available in applying to the vehicle structure - engine block, transmission, suspension, and etc. The other is that light plastic materials can be used in applying to the inner and outer parts of vehicle. 9.1.2 Policy to Improve Operational Efficiency of Transport System Efficient operation of transportation modes The most significant factor is the effect of economic speed in decreasing energy consumption. In the case of autos, gas will be consumed more by 5 liters for 100km runs if the driving speed increases from 60km to 130km. In case of the heavy vehicles, more effect could be expected in condition of the restriction of their highest speed. About 14% gases would be consumed more with about 10% speed increase starting from 100km/h. On the contrary, about 12% gas consumption would be decreased by reducing speed about 10%. Other methods could be additionally brought up such as to discourage a sudden acceleration , stop and start. Transfer to public transportation modes It is definitely evident that enormous benefits are to be reaped in reducing the energy consumption, if the existing private travel users could be diverted from energy-consuming private transportation to energy-saving public transportation. The improvement of energy efficiency, which is gained from the conversion into the public transportation mode, can be seen in the following table. < Table 9.1.1> Energy Efficiency of Autos
Source: British Travel Research Laboratory (TRL)
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