01628729

Component

In 2014, road accounted for 72.8% of all GHG emissions from transportation in Europe. In USA, emissions follow a similar trend. In order to address this problem not only vehicle and fuel type should be considered, but also road design. The main objective of this study is to evaluate the impact of road horizontal alignment on CO₂ emissions produced by passenger cars. As vehicle fuel consumption is strongly related to tailpipe CO₂ emissions, the findings are also applicable to it. A new methodology based on naturalistic data collection has been developed. Individual continuous speed profiles were gathered from actual drivers along eleven two-lane rural road sections. These sections were divided into 29 homogeneous road segments, according to their CCR. CO₂ emission rates were estimated for each segment as the average of all vehicles driving throughout them, excluding the ones not performing under free flow conditions. The applied microsimulation model was VT-Micro. The analysis of the level of influence of horizontal alignment design on CO₂ emission production concluded that emission rates increase when CCR does. Smooth road segments allow drivers to reach higher speeds and maintain them without strong accelerations. Besides, they spend less time at travelling the same distance, so emissions per unit length are lower. Indeed, it was also observed that low average space speeds produce high CO₂ emission rates and they increase even more in roads with high dispersion of speeds along the section. These results may be the base to incorporate sustainability principles to highway geometric design.

This paper was sponsored by TRB committee ADC20 Standing Committee on Transportation and Air Quality.

01618707

17-04284

English

14p

2017

Transportation Research Board 96th Annual Meeting

Digital/other

Figures; References; Tables

Automatic data collection systems; Carbon dioxide; Environmental impact analysis; Fuel consumption; Geometric design; Highway curves; Speed

Design; Environment; Highways

Transportation Research Board Annual Meeting 2017 Paper #17-04284

TRIS, TRB, ATRI

Dec 8 2016 11:38AM