Navigation - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 206

14.1.1 Ecologic Strategy of Navigation
Navigation systems help to find the fastest way to a certain destination. New
systems calculate not only all possible ways but also the routes with the shortest
direction and the smallest fuel consumption across the field [ 7 ].
Route calculation improves services and profits and protects the environment.
Trucking firms usually use a special algorithm for the calculation of the most
economically optimal and least polluting route. This technology offers enormous
profit potential for trucking services. High capacity computers determine the
optimal route within milliseconds. Saving fuel means decreasing CO 2 and pollu-
tant emissions and also a decrease in other pollutants. Self Diagnosis system can
support ecologic navigation in a network due to communication between the
vehicle and an electronic checkpoint.
Congestion in traffic including different accelerating and braking phases of a lot
of vehicles leads to higher concentrations of exhaust gases in the local environ-
ment. Fuel consumption and exhaust gas emissions can be particularly effectively
decreased if traffic light signals are synchronized. Other measures of traffic
organization, e.g., the construction of modern roads, the removal of redundant
crossings, etc., also contribute to lowering the specific fuel consumption and the
specific exhaust gas emissions per road vehicle. However, optimally organized
traffic conditions often lead to an increasing amount of traffic which usually causes
more global fuel consumption and higher global pollution on reconstructed and
renewed roads.
14.1.2 Foresighted Driving
Navigation supports not only the best route but also the choice of the optimal
speed. Increasing the velocity of commercial vehicles weighing 25-40 t on roads
in villages, cities, and highways leads to higher fuel consumption; see Fig. 14.3
[ 8 ].
Not only accelerating but also braking requires surplus fuel. Braking from 90 to
60 km h -1 (55.9-37.3 mi h -1 ) on a highway leads to additional fuel consumption
of approximately 0.7 l (0.18 gal (US) and 0.15 gal (UK)) of diesel fuel. The time
advantage of not driving with foresight is small, because basic traffic conditions
strictly determine the time needed to the destination, independently from short
accelerating and decelerating phases; see Fig. 14.4 .
Higher than optimal speed leads not only to increased fuel consumption and
exhaust gas emissions but also to more accidents. Fuel and emissions can be saved
and unnecessary stops and goes can be avoided with foresight to recognize
obstacles in time by observation and navigation [ 9 ].