Impact of Road Geometry and Surface Types on Fuel Consumption and Greenhouse Gas Emissions
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Date
2018-03
Authors
Solomon, Shiferaw
Journal Title
Journal ISSN
Volume Title
Publisher
AAU
Abstract
Nowadays, it is globally accepted that vehicle gas emission is a significant source of air pollution
and climate change. Correspondingly, vehicle operators are interested in reducing energy
consumption and accordingly fuel costs.
The paper explores the impact of road geometry and road surface types on vehicle emission and
fuel consumption using the Highway Development and Management Four (HDM-4) Tool
emission modeling software. The analysis was based on data acquired from three asphalt
concrete (AC) and two gravel roads located in different areas of Ethiopia. In this regard, the
following data were collected: Road network; Vehicle Fleet; and Work Standards in respect of
improvement and maintenance. The data were entered into HDM 4 and analyzed. The results
indicated that the effects of road geometry that is: rise and fall; curvature; and also vehicle speed;
altitude and pavement surface types are important and should be given an emphasis on vehicle
emission and fuel consumption evaluations.
In all considered road sections, the study found out that emissions and fuel consumption have a
direct relationship with rise and fall. Change of curvature is also related to changes in emission
and fuel consumption. At higher and lower curvatures and at lower rise and fall, both emission
and fuel consumption were maximum but at some point in between the curvatures, emission and
fuel consumption became minimum. At higher rise and fall, emission and fuel consumption
became minimum when curvature got close to zero.
It was also found out that speed has a relationship with emission and fuel consumption. When
the speed lies between 50km/hr to 70 km/hr, maximum energy saving and minimum emission
were achieved. Impact of altitude on emission and fuel consumption was also investigated. Both
emission and fuel consumption increased as altitude decreased.
Another finding was that emission and fuel consumption are most sensitive to road surface types.
Asphalt Concrete (AC) generated most fuel savings and reduced emission compared to Double
Bituminous Surface Treatment (DBST) and Gravel roads. It is expected that the findings of this research will provide insights for policy makers when
consideration of strategies for improving road design to reduce vehicle emissions and fuel
consumption in Ethiopia.
Description
Keywords
Rise and fall, Curvature, Speed, Altitude, Fuel consumption, Emission