REDUCING ENERGY CONSUMPTION AND CARBON EMISSIONS IN A BUS ROUTE: A CASE STUDY IN THE LATIN AMERICAN CONTEXT
Nominated for The Neil Mansfield Award
Xenia Karekla, University College London, Rodrigo Fernandez, Universidad De Los Andes
This study aims to investigate the reduction of bus energy consumption and carbon emissions through operational changes of a bus route in the city of Santiago, Chile. A microscopic traffic simulator is used to quantify the impact of these changes.
Urban metropolises worldwide accommodate more than half of the global population who, due to their activities, are found responsible for 70% of the world’s carbon emissions. In particular, the world’s richest (10% of the global population) emit 50% of the world’s greenhouse gas (GHG) emissions. The environmental harm caused by greenhouse gases is currently at dramatic levels, and finding ways to reduce their impact on air pollution and climate change, in order to improve people’s health and wellbeing, is a challenge that has been taken on by developed cities.
One of the greatest GHG emitters in urban environments, with documented effects on air pollution, is transport systems. Transporting people and goods is a vital activity in cities, however energy related emissions from transportation amounts to 23% of GHG emissions worldwide (25% in Europe and 26% in the USA). Road transportation, in particular, is considered responsible for 70% of all GHG emissions, making it the largest polluter of all transport modes. As an example of the Latin American context, in Chile 28% of its GHG emissions are generated by the transport sector, and with private cars gaining ground over public transportation year after year, the levels of GHG emissions are constantly increasing. Indicative, 45% of GHG emissions from transportation in Chile are produced by cars and taxis, 10% by buses, and 1% by trains.
Enabling people to choose more sustainable means of transport for their everyday mobility could significantly contribute to the reduction of GHG emissions worldwide. Hence, this study’s main objective is to propose a more sustainable bus system by changing the operation of a bus route, with the aim to reduce energy consumption and carbon emissions. A microscopic traffic simulation model of a part of the network is applied to describe the current situation during morning peak hours. Data regarding the bus system, such as bus frequency, vehicle characteristics, number of bus stops, passenger demand, dwell times and other operational characteristics are provided by Redbus Urbano, the operator of the selected bus route. Data related to traffic flow and road infrastructure, such as the number of car and bus lanes and road gradient, are also taken into account. The answer of the research question is attempted through the alteration of three variables: reduction of the current traffic flow, reduction of the current bus acceleration and segregation of the traffic flow by creating dedicated bus lanes.
The impact of the proposed changes on fuel consumption and carbon emissions are discussed in the paper.
Keywords: bus operation; traffic modelling; energy consumption; carbon emissions; road infrastructure.
Association for European Transport