Page 79 - Technology Roadmap Transportation

TECHNOLOGY ROADMAP: TRANSPORTATION

Another interesting result shows that
2-wheelers, cars and heavy duty vehicles Congestion leads to double whammy on
are the major source of different harmful engine emissions. The time cost of a vehicle
pollutants such as oxides of nitrogen, carbon kilometer rises rapidly with increased
dioxide and sulphur dioxide. The generation congestion. This is because the addition of
of these pollutants is higher in Indian a vehicle to an already crowded network
metropolitan cities due to higher mobility. increases travel time for other passengers
Variation in production of major pollutants as well. Since the average speed reduces
such as CO in different regions of India is to levels that are far below the optimal
given in figure 4.11. operating vehicles speed, this leads to
increase in emissions per km, thus the two
Figure 4.12 shows the annual average effects are inter-linked. As an example, the
respirable suspended particulate matter congestion costs are nearly US$ 14 billion in
(RSPM) concentration of major cities in India. terms of excess time required and gasoline
A fluctuating trends in RSPM levels, indicates consumed to the commuters in California,
increasing trend in Delhi, Mumbai and in addition to substantial environmental
Kolkata but for Chennai, it shows decreasing damage. Since VOCs and CO are 250%
trend. The reason for high particulate higher in congested conditions than during
matter levels is attributed by vehicular traffic, free flowing traffic. Therefore, air quality
diesel/kerosene generator sets, small-scale degradation is a natural consequence of
industries, biomass incineration, suspension traffic congestion.
of traffic dust, commercial and domestic use
of fuels. 4.12 GLOBAL ROAD TRANSPORT:
CURRENT NOISE TRENDS
A large number of technologies are currently The vehicular noise now constitutes the
being employed to reduce the emissions of major problem in traffic noise in the highly
these harmful vehicular pollutants from the industrialized countries. The term tyre/
vehicles and a large number of technology road noise denotes the noise emitted from
interventions are therefore being planned/ a rolling tyre as a result of the interaction
implemented to meet the objective of between the tyre and the road surface.
controlling these pollutants. These new Vehicle noise is composed mainly of tyre/
interventions include development of cheap road noise and noise from the powering of
non-noble metal based catalysts for exhaust the vehicle, what is here called power unit
gas after-treatment, on-board diagnostics for noise. Power unit noise is composed of noise
lubricating oils, use of various efficient after- from the engine and all its “accessories”, the
treatment technologies such as three-way exhaust system and the transmission. Both
catalysts, diesel oxidation catalysts, exhaust tyre/road and power unit noise have strong
gas recirculation, selective catalytic reduction, relationships with vehicle speed. First, one
lean NOx traps, particulate traps, plasma shall recognize that tyre/road noise level
traps, fuel borne catalysts etc. increases approximately logarithmically with
speed. These targets aim at attaining the long
Modern interventions are also required for term protection of human health ecosystems
better understanding of pollutant formation and precious resources by reducing noise
processes inside the engine cylinder levels. Reducing transport noise by up to
and therefore, advanced laser diagnostic 10 dB (A) through a systems approach
techniques and micro-sensors have a huge including better indicators and improvements
role to play in control of pollutants from the to vehicles, tyres and infrastructure is in
engine systems. There is also a great need progress. Acoustic engineers have worked
to understand the role of pollutant sources in the vehicle and tyre industries in many
in an automobile other than engine such decades with the aim to reduce or at least
as tyres and better understand road-tyre limit noise. Many governments have agreed
interaction, which leads to formation and on regulations and directives that limit the
emission of large number of nano-particles maximum noise emission levels from vehicles.
into the atmosphere.

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