Real World Driving: Emissions in Highly Congested Traffic

Abstract

The emissions from vehicles in real world driving are of current concern, as they are often higher than on legislated test cycles and this may explain why air quality in cities has not improved in proportion to the reduction in automotive emissions. This has led to the Real Driving Emissions (RDE) legislation in Europe. RDE involves journeys of about 90km with roughly equal proportion of urban, rural and motorway driving. However, air quality exceedances occur in cities with urban congested traffic driving as the main source of the emissions that deteriorate the air quality. Thus the emissions measured on RDE journeys may not be relevant to air quality in cities. A Temet FTIR and Horiba exhaust mass flow measurement system was used for the mass emissions measurements in a Euro 4 SI vehicle. A 5km urban journey on a very congested road was undertaken 29 times at various times so that different traffic congestion was encountered. Each journey was split into ten sections in order that the location and traffic conditions of the highest emissions could be determined. It was found that low speed stop-start traffic has much higher emissions than for freely moving traffic and most of the higher emissions on the longer 5km journeys occurred in relatively short sections of slow moving stop/start traffic. The journey used passed a roadside air quality monitor that exceeded the EU NO2 and PM standards on an annual basis and it was located by the most congested part of the route, where the traffic emissions are shown in this work to be at their highest.

Investigating Particulate and Nitrogen Oxides Emissions of a Plug-In Hybrid Electric Vehicle for a Real-World Driving Scenario

“…Emissions from passenger car transport play a major role in air quality and climate change. Various publications from recent years have shown that there are in some cases considerable variances in emissions in dependence of external criteria such as driving cycles or test route characteristics such as altitudes, traffic congestion and operating or outside temperatures [1][2][3]. Therefore, uncertainties remain, as current emission inventories and databases do not capture all these variances and thus do not represent the actual emissions of all vehicles models or driving situations.…”

High spatio-temporal resolution pollutant measurements of on-board vehicle emissions using ultra-fast response gas analyzers

“…The measured pollutants at such monitoring stations are affected by the dispersion of the pollutant from its source (e.g. vehicle tailpipes), with both climatic and traffic conditions causing variations in the measured air quality (Khalfan et al, 2017). Some urban authorities issue "live" contour maps superimposed on city street maps to inform the population of the current air quality (Kings College London, 2013) and enable the general population to plan their travel routes accordingly.…”

Transition to Electric Mobility in India: Barriers Exploration and Pathways to Powertrain Shift through MCDM Approach

“…Furthermore, due to higher efficiency, reduced fuel consumption and RBS, HEVs have lower emissions throughout their lifetime compared to CVs [ 136 ]. Hence, HEVs are more eco-friendly than CVs and EVs at least until a significant development in battery production and technology or electricity generation occurs through RES [ 137 – 139 ].…”