36
M. L. de Barros Baltar et al.
1 Introduction
The high degree of urbanization and the economic growth of the cities, although
opening the way for countless achievements, also introduced challenges such as
traffic congestion, which is one of the major urban problems faced in recent decades
[4]. The reason is that congestion generates road interruptions that cause travel time
delays [15], excessive fossil fuel consumption and increased environmental pollution
[22, 33].
Congestion can be intensified by events such as traffic incidents (broken-down
vehicles, accidents, flat tires and others), which generate irregular but frequent road
interruptions, as a result of the intermittent traffic flow, generated by the condition
imposed by bottlenecks on the runway [6, 13, 37, 42].
To overcome these problems, a new transport infrastructure must be designed and
built, or traffic policies must be developed to manage and control the traffic flow. The
latter is advantageous mainly in a sustainability point of view because it exploits the
existing infrastructure [21], avoiding unnecessary expenses which are almost always
infeasible due to budget restrictions of the management and control agencies.
Thus, traffic management and control strategies are widely applied to mitigate
congestion as they seek to smooth traffic flows, reduce travel time and minimize pollutant emissions [10]. Specifically, in relation to vehicle pollutant emissions, including
greenhouse gases (GHG) and pollutants harmful to air quality, urban areas produce a
disproportionate amount compared with their geographic size. Thus, local authorities
and transport decision-makers strongly need to mitigate these emissions [22].
In this context, this chapter aims to evaluate, through the application of the MEET
model (Methodologies for Estimating air pollutant Emissions from Transport), the
impacts on carbon dioxide (CO 2 ) emissions on express roads caused by traffic incidents, which are related to the speed reduction. Rio de Janeiro city is used as a case
study to evaluate these emissions and to propose mitigation actions. The scope of this
study is limited to CO 2 , considered the major contributor to GHG emissions during
the transportation tasks [22].
In addition, we know that integrated strategies to reduce GHG and air pollutant
emissions result in significant cobenefits [29, 38], such as improving air quality
and reducing public health spending. Therefore, the overall effect of a transport
intervention (or combined effect of many small and diffuse interventions) on CO 2
emissions is more important than any localized effects [22].
In order to verify the impacts, real data are used from approximately 2,800 incidents on Avenida Brasil, the main expressway in the Rio de Janeiro city. These
data were provided by the Traffic Engineering Company of the Rio de Janeiro city
(Companhia de Engenharia de Tráfego da cidade do Rio de Janeiro—CET-Rio, in
portuguese). This database contains the location of the incident, its time and the
vehicle involved.
We use the MEET model [25] to determine the CO 2 emissions because, according
to Bai et al. [4]: (i) it is based on measurements on the road, so the parameters are
extracted from real-life experiences; (ii) it is sensitive to speed, which is an important
M. L. de Barros Baltar et al.
1 Introduction
The high degree of urbanization and the economic growth of the cities, although
opening the way for countless achievements, also introduced challenges such as
traffic congestion, which is one of the major urban problems faced in recent decades
[4]. The reason is that congestion generates road interruptions that cause travel time
delays [15], excessive fossil fuel consumption and increased environmental pollution
[22, 33].
Congestion can be intensified by events such as traffic incidents (broken-down
vehicles, accidents, flat tires and others), which generate irregular but frequent road
interruptions, as a result of the intermittent traffic flow, generated by the condition
imposed by bottlenecks on the runway [6, 13, 37, 42].
To overcome these problems, a new transport infrastructure must be designed and
built, or traffic policies must be developed to manage and control the traffic flow. The
latter is advantageous mainly in a sustainability point of view because it exploits the
existing infrastructure [21], avoiding unnecessary expenses which are almost always
infeasible due to budget restrictions of the management and control agencies.
Thus, traffic management and control strategies are widely applied to mitigate
congestion as they seek to smooth traffic flows, reduce travel time and minimize pollutant emissions [10]. Specifically, in relation to vehicle pollutant emissions, including
greenhouse gases (GHG) and pollutants harmful to air quality, urban areas produce a
disproportionate amount compared with their geographic size. Thus, local authorities
and transport decision-makers strongly need to mitigate these emissions [22].
In this context, this chapter aims to evaluate, through the application of the MEET
model (Methodologies for Estimating air pollutant Emissions from Transport), the
impacts on carbon dioxide (CO 2 ) emissions on express roads caused by traffic incidents, which are related to the speed reduction. Rio de Janeiro city is used as a case
study to evaluate these emissions and to propose mitigation actions. The scope of this
study is limited to CO 2 , considered the major contributor to GHG emissions during
the transportation tasks [22].
In addition, we know that integrated strategies to reduce GHG and air pollutant
emissions result in significant cobenefits [29, 38], such as improving air quality
and reducing public health spending. Therefore, the overall effect of a transport
intervention (or combined effect of many small and diffuse interventions) on CO 2
emissions is more important than any localized effects [22].
In order to verify the impacts, real data are used from approximately 2,800 incidents on Avenida Brasil, the main expressway in the Rio de Janeiro city. These
data were provided by the Traffic Engineering Company of the Rio de Janeiro city
(Companhia de Engenharia de Tráfego da cidade do Rio de Janeiro—CET-Rio, in
portuguese). This database contains the location of the incident, its time and the
vehicle involved.
We use the MEET model [25] to determine the CO 2 emissions because, according
to Bai et al. [4]: (i) it is based on measurements on the road, so the parameters are
extracted from real-life experiences; (ii) it is sensitive to speed, which is an important